There are a lot of lazy people who just don't want to bother cleaning their guns. At least its what I've concluded.
You don't need to look over your shoulder to see if the DI is watching. He's there, even if just in spirit. Remember, he's kind and gentle and will remind you of your failures.
In all fairness, many of us overclean our guns. And we over lubricate them. And it does no harm. On the other hand, under cleaning and under lubrication will certainly do significant harm. So we mostly err on the side of compulsive cleaning. Its a good thing. Even if you don't over clean every time, doing it once in a while is good.
I have a son who has never cleaned a gun. Ever. And he probably shoots more than me and the other son combined. Pretty scary stuff. But I've worn out one set of lips preaching, so I'm done. If he wants nasty gritty handguns, its OK with me. I guess. I just don't want him to inherit any of my treasures when I die. There are people who should own and shoot Glocks, he's one of them.