Developing a cheat does not ruin anyone's fun. The same goes for guns, knives, anything that could be used as a weapon. It's all about how you use a tool, and in this case creating the tool is fun. Unless you think that everyone who fires a gun for fun, or creates a knife or even just a baseball bat, is a murderer?

So people develop cheats only to not use them in public games, and not distribute them to others?