Yeah, it most likely isn’t an exe but a Linux binary! Other than that, you can probably run the server on your computer pretty easily. You probably won’t be able to host anywhere close to the number of players the official servers do, but that’s just a matter of stronger hardware.

So yeah, they don’t provide the server because they’re “evil”.

They could also do the bare minimum of patching the game so it allows any server and avoid stuff like certificate pinning etc. and then provide an OpenAPI specification for the server and let the community create their own server if they want.