I’d argue that, fundamentally, Tattletale isn’t a bad person, she is someone being held at gunpoint, who’s only real weapon when cornered is digging into people’s psyche for their own problems. Would Amy have done the same thing if Tattletale hadn’t brought that up? Maybe, maybe she would. It wouldn’t change the fact that their family is still fucked up and needs some therapy, and that, as well as Amy’s listlessness with her powers, probably contributed significantly. Tats is still mean, though.
I certainly don’t think Lisa is anywhere near as responsible for these things as Amy thinks. I mean, sure, Lisa’s been known to mess with people’s heads, but ultimately all she did was remind Lisa of the potential for her secrets to come out and mess things up. Then Amy went through a lot of stress because of Leviathan and her dad and Gallant and Bonesaw and Mannequin and Siberian and… you get the point. I think Lisa is for the most part a scapegoat for Amy’s stress, even if Amy doesn’t realize it.
Yeah, it was a dick move on Lisa’s part, but not much more than you’d expect during a confrontation between hero and villain. Hell, Amy herself said some really mean things during that confrontation, too.