Well, that's a lie, there is a very SMALL amount of fandom knowledge required, and that is this: Edward Elric, the Fullmetal Alchemist, hates being called "short". Or "small". Or "tiny". Or any other such synonyms. And this character trait apparently carried over to his minis.

When Good Walks Go Bad: In which Joyce doesn't know what to do, Singsong laughs hysterically, Brenden is unfortunate (as usual), Anjilly ignores her partner, Library is worried, JF is slightly confused, FullMetal is livid, and All is the only one with any sort of power over his not-quite-brother-but-close-enough-to-it