They didn't hold him for refusing to answer. They held him because he was suspicious. That's their job. When everything checked out and they couldn't find anything wrong, they had to let him go.

He was only there for half an hour. 30 minutes. That's not an unreasonable time at all when you've done something suspicious like answer routine questions rudely.

Don't get me wrong. I think our airport security is absolutely useless at this point. I haven't flown on a plane for a decade because I won't submit to that useless idiocy. (I might do so if it weren't useless, despite the 'freedoms' lost.)