In fact, it is perfectly legal in most of US. It is on paper illegal in California, but I haven’t seen this law actually being enforced.

Just because you don’t see it, doesn’t mean it doesn’t happen.

I have a relative who processes digital intakes for a CA ACLU chapter, and they get a huge number of interview-related complaints, which get referred directly to legal assistance who are interested in such cases.

My opinion is we likely don’t hear about it because each case is small, and companies have no incentive to publicize settlements.

I’m quite sure that a lot of interview complains get adjudicated. My point is that few if any of those are complaints related to political discrimination.

The ACLU lost its legitimacy when it stopped defending the civil liberties of people they don't agree with.

Nobody is asking you to support the ACLU there, the poster just mentioned that a relative working for the ACLU deals with such complaints on a regular basis. Your opinion of the ACLU doesn't make that untrue.