I don't think it's a matter of every girl in GS hating her inlaws. It's the form of the question posed that elicited the negative stories about toxic in laws. I took your question as something to initiate a discussion on why men tend not to complain about in laws as compared to women and whether there are situations of men not getting along with their in laws. So I didn't think to mention my own experience with mine. Which is fabulous. I love my MIL and FIL. They look out for me and treat me exactly like a daughter. I've got no complaints against them.
And as for guys not complaining much...that's a valid point. They tend not to say anything. But lots of guys out there have bad experiences with inlaws or their wives instigate things - and a few posters in this thread have mentioned that it can be the other way around. But it's different for guys. Someone here mentioned that most men don't live with their inlaws which is true. It's usually the guy's parents who live with him and his wife. So why complain? If you only have to deal with your inlaws on a temporary basis when they come to visit, I think most guys see it as "Ok this is unpleasant. But they won't be here forever so just let it go."
Also, I would suggest that their complaints simply come in a different form than women's. Women tend to vent. They talk to their friends, their sisters, families, they vent here. I'm no expert on the male mind, but their "complaints" take a different form. For example, there's a couple I know where it's pretty well known that the guy and his in laws don't get along. And his way of "protesting" is simply to avoid them as much as he can. Whenever something is up where he has to go see them or they are coming over, he simply finds reasons (usually work) to avoid contact with them as much as possible. He never says anything. He just avoids them.
Regardless of what it is, I think a lot of us - men and women - could benefit from "live and let live" as Silver Falcon succinctly put it.