Door policy is discrimination only in the sense that the very few people at the door have to make a swift judgment on whether your group will fit in. Can this be upsetting? Sure!
> In Germany. Let me guess, they look at your ID to check your name and nationality first.
By this logic liquor stores in the US also discriminate based on person's nationality since they check the ID.
KitKatClub has a strict dress code policy for their sex-oriented events.