Can you see why people would be frustrated by Gates spending so much money to mandate a form of education for the commoners while providing his own children with something that he presumably considers to be much better? Consider especially that the Common Core is regarded by many as contrived and stifling while a more "free" curriculum allows children to put more of their efforts towards things they care about and have talents for.

I'm not trying to present a qualified opinion on why one approach is better than the other or even to describe them in much accuracy-- just trying to provide the perspective of those who are upset.