Who cares what these people think? Though I'd like more context. Perhaps a link to this review and these fangirl responses?

Also what's The Pit?

...Twisted fangirl logic is just so much funnier when you get to see it in action.

Can you give a link? And if it's multi-chapted, which one did you review in?

Fangirls are eternal. The only way to avoid getting bashed by fangirls is to avoid reviewing badfics. The best thing to do is probably nothing; there's no reason to turn the review section into a flame war.
And remember: if the author reads it and learns something, it's surely worth the backlash from others who are choosing to be ignorant. And if they don't, you can feel loftily superior. ;-p

I know no matter what you should remind them that Criticism isn't an insult.
However I have no idea what else to do without seeing the fanfic,review,and their reaction.