Ask HN: Are “Social Justice” questions in job interviews legal?

My roommate is currently interviewing with a consulting firm, and in the third round of interviews he was explicitly asked which social justice movements he supports. He said it was really out of the blue (no pun intended) and caught him off guard. He said something vague about BLM, and in the followup meeting the company brought it up again, saying something to the effect of "we agreed on that, so that's good."

Is this even legal? I was really shocked when he told me about this. I personally would have been really uncomfortable talking about identity politics during a job interview, even though I'm about as liberal as they come. It certainly sounds as if he had expressed any reservations about the social justice movement he wouldn't have passed the interview.