Since his squad would be a small private club, he is not subject to laws about discrimination on any level. Even if he requested only WASP's that hate all minorities, he would not be violating anyone's constitutional rights. Unless his squad turned into something that wielded some economic power that could affect interstate commerce he is perfectly free to do this.
As far as the UN goes, it's supposed to promote world peace and harmony, but all the reps do, including us, is use their economic and military might to impose things on other nations that benefit that benefit that nation, not the world as a whole. All politics are local.
On a more practical level, a christian is supposed to turn the other cheek, that could get you killed around here LOL.