They can surely not take any case if they want to, but not based on race I guess.
they can simply say NO as far as I know. If they clearly state that it is based on your race, that could be a problem.
Well, since the discrimination laws are for the protection of AMERICANS, we foreigners might or might not be included in. This has always been a gray area based on my knowledge. Theoretically speaking, ANYONE in the US shoudl be protected by this law.