Philanthropy is nice but the money they have still came from exploiting the labor of others.

A sane economic structure would not create billionaires at all. Philanthropy is not necessary to solve problems. If you tax the rich and use the money to build a robust social safety net and invest in science, technology and healthcare that benefits everyone.

Isn't that better than relying on whatever scraps the billionaires leave us out of the goodness of their hearts?