Why is Judge Holden considered one of the most evil villains ever?

Often times I see Judge Holden being compared to the Likes of the Qu, AM the shrike and others. But I never understood why

Like yes he is objectively evil, he’s a murdering rapist and does a lot of bad things, but I feel like putting him on the same level as an Aline race that slaughters and then genetically modified humanity to torture as punishment for centuries, or wiping of the Human race minus a few people to eternally torture out of hatred. Among countless other villains, is much more evil then a serial killer, like lots of those exist in real life.

I just don’t think he should really be put into the “S-Tier” of literary villains imo.