There is a popular debate on whether Bill Gates is evil, with his defenders posting here and here.
In short, people hate him for being excessively rich and monopolizing PC software, and praise him for his charitable work.
I think this is backwards. His monopolization tactics were not as bad as some other tech companies. The charitable work is the problem.
His foundation has been a gigantic transfer of wealth from America to Africa. They say that he has saved a lot of lives, but he has really increased African fertility to where it is now a giant ticking population bomb. If trends continue, Africa will be a far greater disaster than global warming or any of the other environmental concerns.