This is a lengthy post -just under a sixteen hundred words- so please bear with me.*
I've been noticing a viewpoint on Sues that is encroaching onto certain pages of the wiki, but isn't actually addressed in the main article on Mary Sues. That viewpoint is that Sues are not sentient or sapient beings, little more than humanoid-or-whatever-the-species-they're-trying-to-be-shaped flesh-bags filled with glitter, while the main article's definition is the following:
"A Mary Sue is a pet character that the author exempts from realism and/or rules that otherwise govern a fictional world. The more that the author exalts this "darling" at the expense of the rest of the story, the more of a Mary Sue the character becomes. Mary Sue is impervious to failure and resistant to all in-story attempts at criticism and humiliation; any attempt at an external critique usually provokes an authorial temper tantrum. With a preference for style over substance, attitude over empathy, and romantic relationships above all others, the Mary Sue is nevertheless a popular character type due to her function as cheap wish-fulfillment."
If you notice, sapience and sentience are not addressed at all in that definition. I'd argue that it's not something you can pin on all Sues as a matter of course, much less say that all characters are sapient or sentient or not because of a few issues that come up. Needless to say, I'm interested in everyone else's opinion, but before I do, let me outline a few ways we can look at this.
For one, from a 'normal' writing perspective, you can't say that a fictional character is sentient or sapient just by fact of being fictional and not actually being alive. Their ability to 'think' and be aware of their surroundings is limited entirely to what is allowed them by the author, and that is controlled. The author controls everything in the piece they are writing, and in cases of bad writing they will have the characters do things that do not line up with the setting or circumstances where characters are terribly obliviously unaware of something they should be, or understand and know things they have no business or normal ability to know. Judging if a fictional character is sapient or sentient is downright impossible due to this.
Secondly, from a writing perspective where you do treat the characters as people, it's the opposite. All characters should automatically considered to be self aware, and thus sentient and sapient beings. They know who they are, what they're doing, and they're the ones making those decisions and learning and understanding things, even in the case of bad writing where things jump the logic line.
That said, you can of course argue that it is on a case by case basis that each character should be judged, on the basis of how they're fleshed out, what the setting is like, and their role in the piece in question and how they act and react and whether they grow or not, and why. This of course renders any blanket statement impossible to make just on that alone.
Finally, there's also how we in the PPC treat Sues, and the fact that we, as a group, do several things that can be used to treat that statement in a method of ways. First and foremost is the fact that something that is not condoned in the least is torture. It's looked down on both in character and out of character, both from higher-ups (Flowers and/or PGs**) and from colleagues (fellow working agents and your average Boarder). Torturing a Sue is Going Too Far, and not just due to the fact that it isn't funny, because as I have illustrated previously, yes, you can make it funny with the right spin or angle.° It doesn't, however, make it right. The fact of torturing a humanoid character implies that said character is able to experience pain and not like it.
The definition of torture, according to the United Nations Convention Against Torture is the following:
"...any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person for such purposes as obtaining from him, or a third person, information or a confession, punishing him for an act he or a third person has committed or is suspected of having committed, or intimidating or coercing him or a third person, or for any reason based on discrimination of any kind, when such pain or suffering is inflicted by or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity. It does not include pain or suffering arising only from, inherent in, or incidental to, lawful sanctions."
Using this definition (which I will adhere to for the purposes of this thread, and I ask others to do the same) eliminates considering Sues as animals or less than animals, especially when the torture of Sues would fall under the bolded clause.
Additionally, there is the continued recruitment of Mary Sues who are either mild or are sincerely penitent, which means the statement can't be a categorical imperative. You need to be aware to be apologetic of previous actions, especially to be able to be willing to repent. It's the recalcitrant ones who are killed after being charged, which also indicates a viewpoint on the part of the PPC as an organization that Sues are aware of their actions. In court trials, the punishment for those who have been decided by the court that they are not fully in control of their actions, be it through insanity, infirmity of the mind, or otherwise not understanding what they did or the consequences of their actions is different from those who have been proven to have full control of their faculties.
This of course, you might think, does not coincide with the various foods and beverages the PPC has that have Mary Sue as a base ingredient, such as Sue Soufflé or Water (for those of you who aren't aware what Water is, it is a beverage made from Sue blood. Why yes, it is glittery), or the acts of keeping Mary Sue scalp belts, or collecting their skulls, and taking all their things, and what have you.
In regards to Sue Soufflé and Water, the PPC Cafeteria is downright infamous for the many questionable foods it serves, to the point where eating from from it instead of being there to socialize with agents besides your partner is an excellent sign of having finally Lost It. The Cafeteria, as a matter of fact, low budget, and cooks who have to produce meals for hundreds (if not thousands) of people every day, needs to obtain ingredients quickly and cheaply to produce something that at least looks edible, even if it is not, in actuality. It is without a doubt very easy to obtain Sue corpses when they're not being fed to monsters and are left out in the fields, steps, hallways, and rooms of various continua, and better than leaving them there to stumbled upon by an unwitting and clumsy canon character.***
Scalp belts and the collection of various shinies are a natural development in an environment of few awards and accolades, little recognition from Upstairs of the combative abilities of Assassins and other agents who deal with Sues, and little-to-no pay****. Having items that show proof that yes, you had taken down this Sue what had sparkling glowing rainbow hair or had a blood dripping katana that would play a Battle Royale if you swung it just right is important in an organization of hearsay, gossip, and rumor, like most organizations that get large enough become. When people are not awarded for their own achievements in a potentially morale draining career, the only option is to provide them yourself.
In short, I don't think we can say that a whole group of something- Mary Sues, in this case- are non-sentient, not aware, and are essentially animals. There are many many ways to view if a character would be self aware or not, and the definition of Mary Sue as provided on our wiki does not contain anything to suggest that they are or are not, just that they are characters designed to fulfill wishes and desires on the part of the writer. It doesn't even address it.
With that all said; thoughts?
*But let's not badger about.
**While I am aware that your average Permission Giver will quibble against being considered a higher-up, when it comes to certain things like what one really, really shouldn't do, Permission Givers do have more sway and pull over things where the matter of what spirit of the PPC is and what can be broken.
°As Noted and given an example here.
***One can theorize that the reason Neville was in such fair shape for fighting and leading the resistance at Hogwarts by the end of the seventh Harry Potter book was more due to the constant invasion of Sues coming for Harry over the last few years than the treatment he and others received at the hands of the Carrows, as no doubt the food at Hogwarts has remained delicious and nutritionally filling, and Harry, while the protagonist, is a bit oblivious as to what most of his housemates get up to and who some students in his house even are. Poor Neville probably spent years 3-7 tripping over usually dead Sues and Stus.
****The average teenager and young twentysomething knows little of the power of unions and other similiar organizations.