Sounds like his actions alarmed fellow passengers and it was investigated.

I'm going to give the kid the benefit of the doubt and say this wasn't intentionally done as a PR stunt, but I'm also going to say that waiting until you've boarded a plane to call someone in an ISIS controlled country and have a really animated conversation in Arabic is a very poor idea.

Sometimes we willingly subject ourself to increased scrutiny to use services provided by companies, this sounds like one of those cases. Everyone appears to have acted conservatively from the safety/security standpoint yet fairly and open minded by listening to his side of the story and allowing him to continue on his way, and issuing him a refund.