Not really true - While USSR , China were not socialist countries per se - Socialism has shown to work at that family level and small village, tribal level.Socialism never failed, because it was never implemented anywhere
So he gave <0.005% of what he made last week to charities. Well, I think a lot of us gave like at least 100x times that much to charities. And his pledge: at best it's literally worth nothing, right now anyway. At worst it means he plans to take >$100 billions (or possibly even more) with himself into the grave, or leave it to his kin (which is just as worse).