why monitoring network activity to avoid cheat usage?

Hello,
As ReShade is relying of library replacement, if a game editor want to avoid it he just need to check this libraries. It has been done for IL2 GB, battleye is also checking for dll, for example.
So why setting up this mechanism which is not so reliable and may eat resources ? For example ReShade is blocking access to depth buffer ofr DCS world, even if you are playing a single player game...

Because having the ability to block the depth buffer in multiplayer is why ReShade is whitelisted by many third party cheating detection engines.