If I want to cheat at their game, that's my right. The game is running on my computer and I should be able to modify anything I want whenever I want. Cheating at games is just an exercise in computer freedom. It shouldn't be prohibited to begin with as a matter of principle.
I actually have little interest in cheating though. What happens often enough is these anti-cheat services will scan my processes, detect my development tools or virtual machines and label me a cheater because of them. Some games literally refuse to even start because of this. They also ensure a lack of Linux compatibility due to their proprietary Windows drivers.
> so at the very least it doesn't do anything obviously malicious and likely doesn't have glaring security issues
Remember capcom.sys?
https://mobile.twitter.com/TheWack0lian/status/7793978407622...
The horrible truth these companies don't want to face is people should be playing only with trusted friends. This would destroy their "massive online game" model so of course they don't want to do it. They'd rather own your computer instead.
Many games use either partly or entirely P2P decision resolution which is easier to game then purely server side. Then also the gaming industry has been downsizing and automating moderation for years now which means typically the companies with the largest online presence (looking at you ActiBlizzard) don't have enough actual moderators to handle reports and they resort to leaning more heavily on these grey area technologies to catch cheaters. It's fundamentally an issue with expense cutting imo.