I am not sure exactly what A ball is, but I know 7 and 8 year olds and at this age everyone should be given opportunities. Sounds to me like it's all about you and your son as you have already prepared yourself to blowoff those "Problem parents" who have the guts to ask you why it's all about your son.
You should do your son and the league a favor and stay on the sidelines.
I have coached my son and his team has won the championship 2 of the last 3 years. I even for your convenience attached a photo of him the night he received the trophy at the baseball banquet. I guess you were wrong but I do know why your not on the sidelines.
Oh, and no parent asked me why it's all about my son as that was not the intention and never was. I have been around baseball as an umpire, a parent and now a coach. There has never been a season when at least one (usually more) parents complain about the coaching, about the umpiring, about playing time, etc. My response has been and always will be "if you can do a better job here you go" You know the funny thing........not one person has ever taking me up on that offer? I wonder why. Stick to the sidelines yourself pal.