I'm not nonchalant like Dohu like I actually gaf a lot and have the most animated reactions over certain things despite my denial bdkandubsbs BUT I also can't recall if there was a time I was ever bullied to that extent like the first snippet they showed from his past memories. It could be just the mind's defense mechanism working but it could also be his tendency to rationalize situations and overlook their emotional impacts on him, thus, moving past his bullying experience as those are not something that affected like they normally would or that they're just merely memories that have gone by.