This. You can't use the whole "troll culture" thing with Meenah because that culture never existed to her. Her culture was basically cartoonishly pleasant and loving.
And of course, you seem to be admitting she'd probably do that and then excusing that by saying other people did that. Unfortunately though you need to remember the kind of stuff those other people had to go through. Hussie himself said on formspring that Scratch is basically the homestuck equivalent of satan.
So now you're basically saying her acting crazy is ok, because a bunch of vaguely related people on a hellish deathworld under the influence of satan working for mega-satan have acted the same or done worse, even though none of those people are portrayed as being good or ok or nice.
It doesn't work that way. She's a violent, sociopathic, and amoral. She has no excuse for it and she has no real reason to be friends with anyone, and given how sessions work no reason to have been picked for it.