I can understand what you are saying, but as others have said, the kids are going to keep playing (Parent's responsibility, not the game devs or even Xbox). The only option you have is to mute them, submit a player review to avoid them, and continue on. One option you have is to try and play in a party. Find some people that you did well with and try to team up. Then you don't have to hear all the childish behavior.
As for the immaturity only coming from kids, that is too funny. I think the majority of it comes from Adults. Look at how many sexual, vulgar, and racist emblems are out there. Some may be from kids but a lot are from adults. It is against the TOS and yet they create them anyways. Expecting kids not to play is like expecting adults to not curse, to complement the other team after the game, and to not throw insults at every turn...it just isn't going to happen.
