Malicious Compliance

Right. The various Civil Rights Acts in establishing proteted classes in placed of public accommodation and associated case law created a standard whereby there does not need to be, for example, an explicit "No blacks!" sign out front. A demonstrated pattern of refusing to serve black customers was sufficient to run afoul of the laws.

In fact, the discriminatory effect doesn't even need to be intentional. If the end result of a policy results in a discriminatory result, it too is a violation of the law. For instance, where I grew up down south, whenever you went indoors you took your hat off. It's respectful and such. Imagine a dining establishment that turned this custom into a steadfast rule -- no one is seated while wearing a hat. Seems reasonable right? Everyone is treated the same! Until you refuse to serve a Sikh customer because they refuse to remove their turban. Now you're discriminating against someone because of their religion, and there's no overarching reason (safety, health, etc.) that a person can't eat and wear a turban at the same time.