My Hero Academia - Manga Chapter 200 leak

Because he's constantly saving countless innocent lives from villains. He's a horrible husband and father, a crappy person to interact with, but he's still a good hero. If he wasn't so good and popular, Shoto would likely have reported him to the police ages ago.

As the other guy said, Because he saves people and does a good job as a hero. also, He's now actively trying to become a better person and correct his mistakes. Granted, it doesn't erase what he did and he's likely gonna have to confront that at some point, probably through Dabi, But, still, give him some credit.