You are assuming Gates had a bad reputation to launder. He certainly had a bad reputation in some parts of the tech world, but I don't recall the average person feeling that way.

Heck, he has probably got many more people who dislike him now because of the global health work, due to the antivax people and the conspiracy theorists. See this petition last year at whitehouse.gov that wants the Gates Foundation investigated for crimes against humanity, and got almost 700k signatures.

[1] https://web.archive.org/web/20201223180912/https://petitions...