I don't have to assign a generalization to fighting games, they're already generalized. As fighting games. Doi. If you don't think Smash fits the genre... I mean, I don't know what to tell you. What is it then? Platformer? Side-scrolling beat-em-up? Every game fits a genre, no matter how loosely. This is a fighting game, through and through. It's got DI and edgeguarding and all these other facets, yes. It's why we all love this game so much more than others. It's more complex. But then again, that doesn't have anything to do with infinites.
I completely agree that we should go against the norm and defy other, semi-comparable communities if something ruined the game. But if something actually ruined the game, we would have noticed it already *cough*MK*cough*. And it doesn't. It just forces a counterpick. And you know what? Counterpicking is a part of the game, like it or not. You can say that a DK main shouldn't be forced to switch off DK, but there's no reason to say he can't. Counterpicking is an established, accepted part of the game, and you should be doing anything you can do to put your opponent out of his comfort zone.
It doesn't ruin the game. At all. It just forces people to start playing the match earlier than they're used to: On the character select screen. Which is fine. So when you scope out and take a grand ol' look at things, he's just another character, in another fighting game, with another infinite.