What I can tell for sure is that the article reports the kid's parents side of the story and their side only. They obviously make the claim that the cops were called because their kid was too good at the sport. The video they edited opens up with the father saying that. But if you read between the lines of what they tell the cop afterwards it is clear that there was a clash between the parents before the cops were called and the article fails to even mention that. If there is recorded footage of the events somewhere whoever wrote that article couldn't find it, just like they couldn't find anyone else who was there to tell what they see happened.

This is far from being high-end investigative journalism and I'm pointing that out.

The only thing we can deduce with some decent level of certainty is that it is the league that fucked up first. Kids are usually grouped by skill level to avoid things like that and they failed to correct that situation for quite some time it seems.