But again its not implausible or any less grounded to not spell out why he chose the clown motif. Its not any less believable that a lunatic would choose a creepy clown image for his persona. Look at The Silence of the Lambs.They never explain why Hannibal Lecter likes to eat people. Why does some intelligent and cultured psychiatrist like him indulge in cannibalism? They never say. They just say he's insane and a monster. That's all you need. We don't need any insight into it. I know later movies go into his background, but Lambs stands strictly on its own without needing any of them. As does Lecter.
But even then with Joker you can put two and two together yourself just looking at him. He has a facial disfigurement in the form of a perma smile.
Okay, you know how they say that a lie is more convincing if you mix it with the truth? You notice how it's not that a lie is more convincing if you mix it with truths that you don't spell out but someone could guess at? Or that it's more convincing if you tell one story, then tell an entirely different story, but there's a common element to the stories that might be true and would make sense if it was? It's not the same thing.
Superheroes fighting supervillains is naturally less believable than serial killers, so it requires a greater level of diligence in grounding things in reality to make it seem real. It needs the "lie" mixed with the "truth", not to be technically more realistic, but to have greater verisimilitude. Batman Begins delivered on that for me, which is how it won me over on the grounded take when that wouldn't have been my first choice, and then I felt The Dark Knight was approaching it in a more standard way, while styling itself as if it were even more grounded, like it was Law and Order: Super Villains Unit. That just wasn't doing it for me. I'd prefer it to be either more convincing or more fantastical.
We're not talking about the money, we're talking about the clown make up. They say he utilizes it to scare people. There's nothing in the movie that contradicts that. The opposite in fact given how we were shown to instances where he got right up in people's face and started telling them about his scars. He's obviously using his clown image there to intimidate them. The Joker is very much grounded. Not giving specifics about how he came to be doesn't make his actions and crazy logic he utilizes to justify it any less grounded in material.
The movie lays it all out. Joker is like the logical reaction to Batman. The law has a theatrical presence enforcing it, so the underworld got a theatrical presence to react to that. The Joker is the opposing force in every way to Batman. Batman wants order, Joker wants chaos. Batman believes in the good in people, Joker thinks everyone has a price, a breaking point that can turn them into something as bad as him if pushed. Batman operates within a set of rules. Joker has no rules. Batman is dark and grim. Joker is colorful and flamboyant. The Joker is a very well laid out character in who he is and what he wants. The fact they don't give you specifics on how he came to choose the clown motif, despite many strong indicators being peppered into the movie, doesn't make him any less a well laid out character.
I'm not judging his overall merits, and him thematically counterbalancing Batman doesn't have anything to do with the the narrative plausibility or groundedness. And the guy who says he does it to scare people had never even seen him in the makeup. Even if The Joker said it himself, he was shown to be an inherently unreliable narrator when he changed his story on how he got his scars. You can say he does it to scare people because he gets in their faces, but Pfeiffer's Catwoman got in someone's face in a creepy way, and she dressed up like a cat because she was pushed out of a window, got licked by a bunch of cats, and lost her mind. Maybe The Joker uses the clown makeup as a means to an end, or maybe he's making a statement, or maybe something in his past compelled him to do it. We don't know the context. Batman Begins breaks Bruce's path down piece by piece. It spells out how and why Jonathan Crane first put on the mask and how it progressed from there. For me, there's a difference between doing that to make an unlikely character type convincing and just asking me to guess why. And it's more rewarding to me from a grounded reimagining perspective.
That's unfortunate. The Joker's mystery is one of the most attractive qualities about the character, IMO.
I mean, criticizing the mysterious backstory in general wasn't really my point, but I prefer the Nicholson approach to his background. Or the Phoenix approach, although that's a lot of background detail.