Yes, the school should be more interactive but why look at what someone else can do or has to do when the first response is what is MY responsibility in this and what do I teach my child? What can I do to support him in this situation?
I would suggest that you go to the store and have him pick out his own ball that he can play with at recess. How long do you think it would take for someone to go over to him and ask if they can play with him? Make sure you put HIS name on it so no one tries to take it away from him. And remind him how he felt when he was told “NO” when he asked if he could play. Lets see what develops from there. The one who owns the ball holds the cards. What lessons does he learn from this?
Number one there are solutions to every problem.
He can always come and discuss things with you and the two of you can work on problem solving.
He does not have to try to be part of a crowd that doesn’t value him, he has to recognize his own value. So in essence be a leader and not a follower. If others want to play with him, he doesn’t have to be stuck up and be the kind that says “no” or “i’ll think about it”. He can be the one that says, “sure, everyone counts”.
Always stand tall and proud, don’t let others devalue you or attack your self-esteem and self-confidence.