What does that matter? The restaurant is open to the public right? So all of the public should be allowed to eat there, including the KKK if we follow the logic that we've seen from you over the past few days.
The KKK Members affiliation is not protected under the Constitution. Neither is a Black Panthers affiliation. Both can legally be refused service.
Nice try, but no. You'd file your lawsuit claiming race discrimination. Blacks for years have bitched that whites have used covers, and they win. As a practical matter, you CANNOT simply say "I don't care they're black, I don't like their pants drooping", etc. and you will STILL GET SUED UP AND DOWN and... YOU WILL LOSE.
Got it?
So, it's kind of delicious to imagine blacks squirming over the KKK hypo.
Sorry man, behavior is relevant. Dress codes are relevant. Upsetting the place is relevant. Get over it.