They're not openly discriminating so much as the guards are giving literally every excuse possible to not let the niggers in. This happens all the time in lots of businesses in America, they turn away darkies and say "Its not a racial thing" when in truth they just don't want to put up with nigger bullshit. Covert discrimination is the name of the game but occasionally you have snitches like the guard mentioned in OP's article who crack under pressure and tell the authorities and the press whats really going on.
Why take the risk.
Niggers are not only loud and obnoxious, they're outright hostile to white male clubbers and hands on white females. They will gang up on white dudes who bring their girlfriends and pull all sorts of bullshit to try to cuck/humiliate white guys. They order tons of drinks and never pay, and if the bouncers have to get involved they close ranks. Too many niggers at a club and suddenly its just a free watering hole for nogs, negresses, and a few drug-addicted mudsharks that isn't at all profitable. So yeah its worth the risk to keep niggers out as long as possible.