So I went to play online yesterday, tried For Fun, and. . .taunt party.
I (mostly) complied out of politeness, but I was kind of looking forward to having a free-for-all right then. . .
That's why I decided to figure out how to stop taunt parties from taking over online. The solution is simple, really.
Give them their own online mode.
As the compassionate and logical person I am, I realize that their way of playing the game is every bit as legitimate as ours and there's no way we can simply purge their behaviors off of online as they will always adapt and then resume having parties.
So let's give them a mode where instead of a normal match, you have a timed match where you can't take damage and the taunt limit is lifted.
And at the end of each match in this mode, the victory screen shows all the characters used in that match laughing as the announcer says: "The winner is. . .everybody!"
So yeah, problem solved.