The way I see it, there's two kinds of hackers in (multiplayer) games.
First, there's the people who make the hacks. More often than not, they just do it because they can. They want to show off their 'sk1llz' by creating an aimbot or save editor whatever.
Then, there are the people who use the hacks. They just suck at the game and need an unfair advantage to be competitive, because their puny e-penis will shrivel up and fall off if they'd lose a match.
In singleplayer games though, everything is fair game. There's nothing wrong with cheating or hacking in a singleplayer game, because even if you are ruining the whole thing, you're still only ruining it for yourself.