Child's Play

I try to think rationally and calmly when it comes to my kids. Of course, I'm usually not successful in this regard, but I do try. However, when I see my kids being hurt -- physically or emotionally--by someone, I'm like a bull who sees red! Here's what happened recently: a friend of mine has a son in my son's 1st grade class. My son seems to idolize this child; I'm not sure why. My son had a birthday party last month, and I insisted he invite all of the boys in his class, even though there were a few he clearly did not want coming to his party. Now, my friend's son is having a party, and my son was not invited (as well as some other boys.) I can imagine how devastated my son would be if he were to hear about the party, and I think he probably will. I just feel so strongly that every child in the class, or at least all of one sex, be invited to a 1st grade birthday party so that no child will be hurt. I am LIVID that this friend allowed her son to come to my son's party but didn't feel she had to reciprocate! Being a wimp who tries to avoid most confrontations, I sent her an email (instead of calling) asking that she make sure her son not talk about the party at school to avoid hurting my son's feelings. I have yet to hear back from her. (I tried to make the email very businesslike, and I think I succeeded.) Am I wrong to be so angry about this, or should I have ignored the situation?