I agree, if we are talking about the extreme parents. There are the extremely over-competitive ones who spoil the fun, and at the other end of the spectrum the apathetic ones who don't nurture their kid's interests. But the article title doesn't suggest that it's merely referring to those extremes when it states generally that kids would be better off without their parents at their games.
We have already gone pretty far down the path of normalizing the idea that kids are better off separated from their parents as early as possible and for as long as possible via public schooling. Because of this many parents spend very little time with their kids as it is. Suggesting that we might still have too much influence on our kids in the limited amount of time we have left to spend with them in sports,, and that we should instead yet again hand kids over to others and get out of the way, is disturbing.
These activities and sports, which are almost always volunteer driven, only really function well for the kids, or exist at all, because of parental involvement. I'm happy to watch my kids in their activities and sports, I help those groups wherever I can so more kids can benefit, and would encourage others to do the same. Parents are an asset to the kids and their groups, not the enemy.