Haha that is frustrating. Here's my take (sorry if I seem to ramble). Honestly, I would just tell that particular parent well then I guess your child is not going to play this year.

I have helped run community leagues and have coached 15+ years and I think it just comes down to establishing the ground rules with the parents and players from square one. 1) I am in control of everything related to team. Understand that you, the parents and players, are not involved in any of my decisions with relation to the roster. I will make the best decision for each team. 2) Your child will be allocated to the team of my choosing. This choice will be based on merit alone. If your child does not make the team, then this means they have not achieved a level high enough to be included on the team. If you have any problem with this you have two decisions: Either agree with me or simply your child will not play. (so really one decision)

I would not even entertain this bizarre entitlement bs and as long as you have the support of the school then who cares what the parents say or what kids drop out.

Furthermore, it's bad for team chemistry if some kids know that other kids are there based on something else other than merit. And as a coach that is what you are trying to do; create a team environment and culture that is fair. I think your regular, average parent and player appreciates a coach that is not going to be manipulated and will tell the difficult parents, I hear what you are saying but at the end of the day i'm the coach and I make the rules. I have never had a problem with parents because from day one it is established that I am in control.

Also if a parent is punishing their kid for not making a team. All that means is that they are a shitty parent. There is nothing you can do about that. It sucks for the kid but your job is to run a team. I wouldn't get sucked in to the drama/politics of the decision. If that kid really wants to play he or she is going to do whatever it takes, even if it means driving that parent crazy or going behind their back.

There are also nice ways of telling people to f off. "Oh Mrs. So and so I hear what you are saying and I will definitely take your comments into consideration when I am making the final rosters." --> does nothing or cuts child. Haha.