Harold's been a tsundere for so long that people are not being afraid of his harsh remarks but rather takes it as a term of endearment.
I still don't get why he can't break out of that way of speaking. He's not acting. When he wants to say something nice he ends up saying something rude.
Lol, that Clark Kent level disguise though. Change of outfit, a pair of glasses mask, and that's it. Exposed crimson eyes, black hair, boyish voice, boyish build, and even that same potty mouth. Oh jeez, whoever could it be?