Because Nathan actually thinks that the world is a nice place. Bad stuff happens, but to him it all works out in the end. Nothing is completely scary yet, and he's got all his dreams and his hopes and his faith that there's good in the world. I want him to stay that way for as long as possible.

[Of course it'l only be temporary, everyone had to grow up and deal with stuff. But the thing is - the concern that Mikado might have somewhat grasped - that he might get into stupider shit by hanging around with boys older than him, that had understandably different views of the world.]

If you try to get him involved in that then I'll forget that the both of you even exist.

[Or she'll beat the shit out of them. One is much easier to contend with than the other.]