I agree with your parents. I failed to learn about anything from this essay except for this one thing:
I have the opportunity to set a standard for my teammates. By making plays, I can inspire them. A diving catch, just as much as it stops a run, fills a team with adrenaline. Sensational play provides confidence and motivation.
It seems like this is the overall lesson that you have learned from baseball and if it is, you need to make that more clear. If not, spend the latter part of your essay describing what you have learned from this community. Also, the first paragraph needs some reworking. I want to hear about the baseball community team, not the specifics on how to play. Your parents are correct in that the essay seems individual vs community and that's not the way it should.
Your passion is clear in this essay but you haven't written it down correctly yet.