That sounds a bit harsh.

Unless you're going for a role that requires some kind of explicit/specific knowledge - and you're clearly not able to demonstrate any skill in that area - I wouldn't put too much stock in the interview processes of Unicorns actually being indicative of your true skill.

I've been told, during an interview, that I was clearly incompetent and the interviewer terminated the interview. This was because I stumbled on doing a series of whiteboard exercises to solve some obscure brain-teasers.

I ended up getting the job anyway (I had worked with people there, and they vouched for me) and learned that to many of the interviewers, they found great delight in finding the most obscure and weird problems, trick questions and coding challenges.

It didn't help with selecting for competency, and the product the company was shipping wasn't exactly ground breaking or needing of someone who could on the spot solve arcane bullshit.