Only people of a certain age who grew up after Bill left MS ever thought he was a good guy. Prior to that he was fairly universally hated. The Bill and Melinda Gates Foundation has done good things but that's kind of like outsourcing your human decency because you can't figure it out yourself.
Those people who thought that only did so because they did no research whatsoever and into his "charity" work. When you look closer at The Gates Foundation you start finding a lot of troublesome shit. I wouldn't even classify it as a charity, it's just a way to spread money around to their rich friends.
Kinda like how everyone thought Bill Gates was a good guy
The only people that ever thought this were those who knew virtually nothing about him... he donated a lot of money to a lot of causes, but got it all through dodgy ethics and cutthroat, scummy business practices. It was pretty well-known that he had (a?) mistress(es?).
And I use "he" lightly - his wife pushed hard for the philanthropy, and it's not likely that he would have done so on his own.