They will only get in trouble if first they ban people of a protected class, and secondly it can be shown that their stated reason for banning was a lie covering their desire to actually ban people of a protected class or represents a bias against those members merely via statistical fact.

Merely being arbitrary in enforcement or inconsistent isn’t enough to automatically trigger government protection.

If you say that this isn’t fair, then I agree. However the class protections are pragmatic and serve to reduce social disruption. Like it or not, people are a lot less worked up over being discriminated against due to being democrats, than they are for being Catholics.