This. I feel like the point of the characterization is that all that bravado is largely empty.
The thing that I find weird about the criticisms of MHA's characterizations is that one the main themes of the show is how heroes are not going to be what you think they are or should be. I think most people are aware of this idea ("Never meet your heroes.") but this just becomes
So when I see people complain about a character not acting or looking the way they want them to, I'm just like... that's the point?