Back in the early days of video games, it was rare for people to actually beat one. The difficulty was inflated to create long term interest. You didn't just play things from start to finish and watch cinematics while pressing a button occasionally. Playing a game was about mastering it.

So, to game developers in the less-early-but-still-early days, letting people cheat their way through even a single player game was a danger in that it took away the prestige of actually succeeding by normal means. It was a shameful thing to do despite the triviality. To them, getting a high score or completing a game was serious business, and cheating deserved countermeasures. Nowadays people openly cheat in competitive games where it DOES impact other people, with no remorse. I would prefer the extreme where all cheating is treated like crime over the opposite where people are proud of their ability to install an aimbot.