The important thing to realize here is that more than one person can be the ass hole.
OP felt the need to sit with her son and make sure he was eating properly. Otherwise, he would not eat as he is supposed to. I do not have enough evidence to determine if that is true or not. That really is not important, so I will assume for the sake of argument that it is true, that the boy wouldn't eat properly without parental super vision.
I think that those people who criticized OP should not have. OP’s father-in-law should not have called her out like that. He was the one who made a scene. This was his fault, not OP's. Who does it hurt if OP sits with her three year old while he eats? No one, so OP’s father-in-law should mind his own business.
OP said that some of the men in the family would have been better people had they been babied. Would they though? They are all still alive. Why would they need to be babied? It is too late to do anything now (you can't go back in time and baby them), so what do you really accomplish by pointing it out?
Everything that I just my opinion. If you disagree, I am willing to hear the argument.