[ Because Kasumi would argue that it wasn't his fault he was manipulated by a truly vile human being. That part of the responsibility falls on those around him for not being able to support him -- but she also knows that Tetsuo did everything in his power to push those people away; hell, he even hurt Ken, so while Kasumi might be sorry for what happened to him, she might not forgive him entirely just yet.

But in the first place, no one deserves to die like Tetsuo just did. Made into some toy, some tool for some evil plot, a supposed spectacle for others' horror -- it still sickened her to think about it. ]

Tetsuo. [ she draws in a deep breath. ] I don't know much about the kind of place that you and Kaneda come from--only that it's shitty. But you were mistreated by the world around you, and someone took that hurt and manipulated you. That's not your fault.