That's a pretty shallow thing to say...
Like said before, it's called a role playing game for a reason.
My first/main character is an elf. A Dark Elf at that. Why? Because that's the race
I prefer playing as, because
I prefer those characteristics, those traits, etc. If I wanted to play a game that forced me to play only as one race, I would do so. Dark Elves DO play a part in the game, they are not treated very well, and even have a "grey quarter", and get accused of being involved with the Thalmor simply because they're elven. But because it doesn't "center around their culture" I shouldn't be playing as one? OK...
My second character IS a Nord. I wanted to try out being a Nord and being the "typical" Skyrim citizen, and yes, it's fun, but I still prefer my first character. Being that character speaks to me more. I prefer being an elf, and just because I'm playing a game based on a certain culture doesn't mean I should force myself to play what would be expected.
It's a fantasy game, anyway. I'm pretty sure there wasn't people running around "shouting" each other to death, absorbing dragon souls, etc.
And like Austin Chaos said, this game isn't about the Nords. It's about the Civil War(which yes, concerns the Nords more than the other races, but it still involves the other races), it's about Alduin...it's about what YOU choose for it to be about. You can totally ignore the main quest if you wanted to and just do the faction/side quests. Don't see why you would NEED to be a Nord for those. All races are involved in one way or the other, whether they are treated poorly because of racism, whether they are natives, foreigners, invaders, enemies, etc.
Also, I wasn't aware mafias and gangs only included a certain race...LOL. That's even worse than what you wrote in your original post.