I like Rose a lot, but she's doing the Stefan and Damon thing re: Katherine, only towards Klaus and with 500 years of total certainty she's right due to horrible things continually happening because of it - I don't think Rose really believes any of them have a chance at stopping Klaus, but she's just lost Trevor and she's kind of like "to fuck with it, I guess going out swinging is better than dying scared and alone". And sometimes that leads to her making profoundly bad judgment calls, like telling Damon to stop caring, much like how Stefan and Damon's thing about Katherine leads to Stefan being an overprotective little creep at Elena sometimes and Damon ... being Damon, basically.

Actually, that's probably why I like Rose so much. That and she threw Damon up against a car when he tried to threaten her. (Damon and people hurting him: it's a thing now. It's definitely a thing.)

Also HELL FUCKING YES, KATHERINE, YOU ARE AMAZING.