Because this is Microsoft we shall apply Gates' razor and must thus conclude that "never attribute to stupidity that which is adequately explained by malice".
This is a difficult question to answer without knowing whether your Bill Gates context includes his years at Microsoft, or only as a philanthropist with sketchy friends.
If the former, you'll need to present an argument that Microsoft did not hold back the entire industry for 20 years with low quality products, severe user-hostility, and monopolistic practices.
If the latter, you should read up about the 1980s and 1990s and early 2000s.
Monopolistic actions are malicious, if you believe in free markets. Gates led the war against Netscape, for one. The setback to the industry and consumers was massive.
Anti-market behavior is today completely normalized, so Gates is very much not alone. Malice is not an unusual phenomenon.
I like this term, hopefully it enters dictionary. Stupidity doesn't buy yachts, vile malice does.