Why do people think he is a bad character?
He's had the greatest hand in life, and had everything given to him. He doesn't want to waste that gift, but use it to it's fullest.
But you see, he knows he's unworthy. Because All Might chose somebody else.
He can beat deku in a 1 on 1 fight, any day. So why is Deku the chosen one?
Lets not forget that All Might lost his powers to save Bakugo. Or, as it can be assumed, Bakugo is the reason All Might retired. This is true more so in Bakugo's mind than anyone elses.
The conclusion from this perspective, isn't that he's missing something, but that he's actually a weakling and everyone else is taking it easy. Deku is the example. He seemed to be powerless at first, but suddenly has this God power out of nowhere. It's as if he was pretending.
And of course, when you're born with everything you need to win and succeed, yet people with less can do more, you've wasted your gift. Bakugo thinks this, and quite likely the only reason he is so angry all of the time.
Todoroki should have won. Bakugo won, but Bakugo knows Todoroki should have won. He was going easy on him too.
It's almost like everyone is pointing out how much of a failure he is by not trying, and being captured by villains and retiring All Might is proof of that.
In short, he thinks the world is mocking him for not being strong enough.
In truth, it's not strength he lacks. He can beat Deku 1 on 1, any day. He can beat Todoroki 1 on 1, any day.
But being a Hero isn't about defeating your enemies. That's just one part of it.
Kindness and compasion. Saving people and protecting people, helping others. For that, you also have to conceed and let others help you in return. Bakugo can't have that. He was born the best, and isn't allowed help in his mind. To him, if he can't be the best all on his own, because his powers are the best, then he's a whole lot of wasted potential.
So he just shouts at people to make them go away.
