How come everyone hates Spider-Man dancing, but has no problem with Joker doing it?

I kinda like dancing Spidey.

Because Spider-Man is doing a boring dance in a substandard scene in a weak film.

The Joker dance is the highpoint of a strong film.

Oh, and the song used in Joker is much much better.

the joker is crazy so him dancing is okay

Do you mean Toby Maguire in Spider Man 3? I think because it was out of character for Peter Parker and when the movie came out in 2007 everyone hated the emo punk style by then. Arthur dancing as the Joker was fitting for his character.

Go back and watch most of the old depictions of the Joker, from Caesar Romero to Jack Nicholson to Mark Hamill's depiction in the animated series, all of them danced around. The dancing was different for each Joker, though.

Nicholson's dancing was smug and sardonic, in the animated series the Joker's dances were usually as a way to express glee in his mayhem. I think the only who didn't dance was Heath Ledger.

Phoenix dancing in Joker made sense because he was a performer, and it was supposed to be part of his act. It was also an expression of pain and joy, as well as the revelatory joy he experienced from bringing others pain.

There was a lot of expressive intent and character unraveling taking place during each of the dancing sequences that Phoenix portrays in Joker.

What exactly was Spider-Man trying to say with his dancing in Spider-Man 3?

Because it's the Joker not Spider ya thick twat. Plus it's two totally different tones and feel.

Choice of soundtrack.