Bill is donating his money for 2 reasons; taxes and an attempt to make himself look good similar to Rockefeller and Vanderbilt. Microsoft didn't get where it was by playing nice but it is amazing to see how quickly that was forgotten. I think it was working too except that his friendship with Jeffery was exposed, we shall see.
Ha, that may be technically true but when did you ever find a billionaire who would be OK with it?