I think I've done everything I can to teach him better.

There have been consequences for complaining. You're assuming falsely that that's not there.

To give you some context about the situation, the ref tossed one of the players from the game today for complaining too much about a call he made.

That kid was just saying the same things he heard the parents say. My kid knows better than to say that to a ref.

We are so far away from good sportsmanship and gratitude towards refs in youth sports, it's not even funny. But sure, make this a "you and your kid" problem. Keep your head in the sand.

I think it's possible for other people other than parents to have an influence on our kids. And I think it's possible and OK for parents to not like that influence.