you are totally mistaken.
Unlike Republicans, Democrats want higher tax rates for the rich to BENEFIT the society, not for themselves. I believe that Democrats have more wealth than Republicans - I think Nancy Pelsoi has more money than any other politicians and Obama makes enough income that he'll have to pay more taxes as well.
I do NOT care for charity much and would rather give more taxes compared to a typical Republican for social programs because I consider them more efficient and more fair to all Americans. So, I would donate less to charity while paying more taxes.
More taxes pay for social programs, welfare, military, and so forth. They're more efficient and more fair. Where are charities that will build free roads for you? Where are charities that print welfare checks and food stamps? Where are charities that will pay for military costs? It's not practical.