[ He wasn't expecting that level of honesty when he posed the question, but he does a decent job at keeping his reaction subdued and only looks back at him with measured concern. His experience is sadly not as surprising as it should be. The 'us vs them' mentality led to more bloodshed than he ever wanted to see in his lifetime, and he's feared that it will come to exactly what he's describing if nothing changes.

A glimpse into the future.

That Kaneki openly admits to what he's done says a lot about him. As much as he doesn't like it, Marcos doesn't really have the moral high ground to tell him that violence isn't the answer. He used to believe they could change things peacefully, and he still does, but every time he starts over from scratch it gets harder. ]

I... know a little bit of what it's like, to be hunted. There were plenty of people who only saw us as a danger to society. They decided we weren't human and didn't deserve the same rights.

[ He's tentative, not wanting to pry but wanting to know more. ]

Did something happen that started it?