This is one of the rare cases that I'm fine with OP MC. It justifies his attitude, which is nice for me. Certainly more tolerable than the guy from Mahouka, cool collected boring fucboi
It's a part of his character. He's cocky as hell but it's justified. Apparently he does get brought down to size at some point in the novels shortly after the events of the anime but I never read the novels so I have no idea.