I'm Indian with a beard, and I usually travel alone. I have been a U.S. citizen for almost 30 years, not a dual citizen (gave up my birth citizenship), and I've been through extra screening 9 times out of 10 in the past decade and a half since 9/11. I've had my carry-on bags re-searched at the gate about 50% of the time. Yep, that's a thing they do, I'm sure you've probably never even heard of it.

It's fairly obvious the random screenings aren't random at all, but there's very little that can be done, since no records of these interactions exist to show a systemic pattern, which is what a court of law would want to see.