Shrug, actually, I find Smash tournaments to be a great mixing culture of race/religion/persona (dorks, preps, even athletes). I don't think any one group dominates in terms of skill, but looking at top players from melee:
Ken: Asian (not sure where from)
Azen: Asian (I think Filipino)
ChuDat: hispanic (Bolivian)
PC Chris: white
Mew2King: white
Isai: hispanic
Chillin: brown (where from, not sure)
Neo: black
KeepSpeedn: black
Shizwiz: black
Taj: black
Forward: white
Drephen: white
Wes: black
Bum: black
Mango: hispanic...I think?
shrug, I don't know, I could just keep going, its really diverse, thats the point I'm trying to make, and love our communities diversity. I think one thing that may explain the diversity is that the best players are usually around cities with lots of competition, and cities also happen to have large mixes of different races. Here in the midwest I don't run into nearly as much diversity as I do at DC tournaments, but national tournaments are amazing cause everyone travels to them and you just get like, everything possible.