When I last entered the US in 2009 they took my fingerprints and a photo. I assumed it to be mandatory.
I also had to “please follow me” to a backroom, but I kinda expected this as a muslim. Met some friendly mexican and pakistani people there, so it wasn’t that bad. I still decided to refuse all business trips to the US from that day on (and avoided tourist travel there as well), as I just didn’t feel safe.
It is also illegal in Germany. We love free speech.