Why was King Leopold II of Belgium not more infamous than Hitler?

I'm sure this question's been asked here but I wanted to get more specific. People say it's because they were not civilized Jews they were aboriginal Africans, and that's an easy go to answer. But is that really true? It's an awfully cynical view of mankind. I'm not saying I don't believe it but I was just wondering if there was more reasons than just that as to why he is not more infamous even though he killed nearly twice as many people as Hitler