Fine, Calvin didn't want to be called a terrorist. Kitty understood it was a trigger--his reaction made sure of it--but it didn't spur her to back down in the least. Instead, Kitty remained just as defiant, rolling her eyes when he basically implicated naivete on her part. "Oh, please," she retorted, hand thrown up dismissively. "You think I don't know that? You think that I just sit here in a bubble, seeing what I want to see through rose-colored glasses?! I've been out there, Calvin, I've had my experiences, so don't presume to tell me what I know or do not know about this world. In case you've forgotten, I'm a mutant too." Maybe their hardships weren't exactly the same, but Kitty knew what it was like to have the world against her and somehow come up with the will to continue to fight for it and for herself. The difference was that she didn't think she needed to wipe out the entire human race in the process.
When it seemed like she had really struck a nerve, Kitty tensed and took a step back, watching him warily with her brave face on. She took that moment to bring her own emotions down a notch, because she could feel a headache starting to come in and her body trembling. Kitty stayed quiet, not even proud to have stumped him, and stared down at the ground, taking in all that Calvin was saying. She had no doubt in her mind that he thought about leaving, but it did confuse her to no end as to why he continued to stay with them. And apparently he was just as confused, and it was only then at his last confession that Kitty looked at him, expressionless. She had to think here, she had to figure out what the Professor would have said or done if he were in her position to hear this. And, well, she had something of an inkling--there was something about second chances floating around in her head--but she wasn't entirely confident about what she was about to say next.
"Listen--" Kitty shut her eyes and took in a slow, deep breath. "You're obviously not obligated to stay here anymore; the world's turned to crap and you don't have that thing on you. And I stand by what I said; if you choose to leave, I won't stop you. But--" Kitty held up and earnest hand for him to hear her out and inched closer, her heart pounding with anxiety. "You have a home here, if...if you...want...it."