I have no problem with kids peeping. Part of the fun growing up, as scummy as it is.
But he DID know what the hole was and what he'd find looking through it. I mean he said all himself, so not sure why you MFauli are making him to be some innocent ignorant bystander. He knew full what he was doing and what he was going to see through it.
Edit:
So All for One can forcibly steal Quirks, and One for All can only be transferred if the users wish it.
Wonder how that will work when they clash with one another.