> they couldn't just tell you whatever applicant attributes they wanted

It's possible that the applicant attributes they wanted were a violation of U.S. labor law, but they also knew that as long as they didn't explicitly say it, they couldn't be found guilty of violating the law later, so they leave it to you to guess.

They were lying. They didn't actually want to hire anybody, but wanted to pretend they were, so they change requirements whenever it looks like somebody might actually meet them.

This was also one of my first questions. They made it sound like there were a lot of small nuances and they could not afford to spend the time working them out in detail ahead of time.