I feel that everyone's character is a shitty self-insert. The author has no choice but to make choices that support or punish certain actions, traits, and behaviors. Inevitably, even a character who looks or acts nothing like them will eventually end up learning to be more like what the author wants, because that's the extent of what the author knows.
It's like, you can't draw with a color that doesn't exist, or build houses out of air.
At least if you're obvious about it and allow the audience to kind of hate you for it, you can skip ahead to the fun parts instead of trying to make your protagonist some kind of religious icon. Nobody's a paragon, especially when we all value different things.
That being said... when a self-insert gets everything they want (money, a harem), and it's all a power-fantasy or a "look how much punishment I can take" dick-measuring contest... I'm out. No character is interesting if they always win.
The people who worship a fictional character are usually the ones who grew up with them, and weren't old enough to see things like... part of Goku's charm is that he's oblivious. Indiana Jones is a jerk. Superman is inherently ridiculous and kind of boring, and Spider-Man is a creepy slacker.
Or with actors, like how Jim Carrey is actually kind of a freak, and everyone knows it! But they like him anyway. He's not a "God", nobody worships him. He just works really hard to be entertaining, and says what we all know and what he knows we all want to hear or say.
