You know, I'm really tired of hearing "it's beatable" as a reason for not taking action against something. You know what else is beatable? Murder. Just pay more attention to the world around you. Work out a little. Get a concealed weapon license and learn to use it. Walk with swagger and no one will **** with you. See? Murder is totally beatable if you just put forth more effort, but we ban it because we're scrubs, right?
Oh, what's that? Murder is totally different because it isn't fair and real life isn't comparable to competition?
A ) Try telling Charles Darwin that life isn't a competition. It's already been proven that life IS competition at its core, and our society only reinforces that. Try again.
B ) As I said, totally beatable. If you are victimized by murder, you weren't living to win. If you get away with it, your victim wasn't living to win, either. Live to win, and you'll never be murdered because you'll always be paying utmost attention to your surroundings and you'll always be protected.
So, why are we ok with banning murder? Simply put, because society has decided that it doesn't want to deal with that anymore. We keep saying that we have all these reasons why we can ban something, but ultimately, the reason we ban ANYTHING is simply, at its core, because we don't want to deal with it any longer. We don't want to deal with stalling, overcentralization, etc. If we don't want to deal with something, we can FIND a justification (see: Stage Bans, which were pretty much decided a week after the game came out when people decided they didn't like stages and found reasons to justify bans WITHOUT tournament experience).
The thing is, now the community is changing. Panda's poll and this thread (plus others) is showing that the new community wants a different experience from their game. They aren't willing to put up with the same crap that the old community would be willing to. Old-school Smashers call it being "scrubs", but really, that's just hypocrisy; in Brawl, we're all scrubs, just some scrubs are accepted by the majority. I don't like some of the stuff, either, but you know what? Life is competitive, and life changes. Adapt or lose. If you don't like the way things are turning out, there are plenty of other games to play. Adapt and change with a community that wants a different (what some people call "scrubby") experience, or leave and play another game.
From the sounds of it, people aren't going to want to deal with some things (like, obviously, planking) for much longer.