Apparently Washington high school sports has a ban on all endzone celebrations, which is why the penalty was called.
But still, it's not like he was putting the ball with a pylon or bowling with the ball to celebrate. The celebration didn't cause a delay in playing, which I think is why they ban endzone celebrations.
Political correctness issue? Not in this case. It's just an absurd rule.
Now, if there was some rule banning any kind of religious display in sports, then there would be a major problem.