I'm English and I have very nice teeth. But hey! You should have seen them before. I've got caps and been going to an American dentist for the past 20 years. Down the pub in London now when I smile and order a pint they think I'm a tourist.
No, English is a nationality, not a race. Besides, that would just be stating the obvious. Haha just kidding, there's a few of them that have straight teeth. It's like saying they don't bathe everyday or use deodorant. While it's true for most of them, it has become politically incorrect to say it out loud.
You suggest that this is genetic, which is it is clearly not when you look at the evidence, see face book Y Crooked Teeth or orthotropics.co.uk If it is environmental then it cannot be racist.......QED Mike