Women, why would some men think we don't know what kinds of things men say in the "locker room?"?

Regarding Disgusting Donald’s comments, I have had 2 men on my Facebook feed (both pro Trump) say, “Meh. No big deal. If only you knew what kinds of things are said in the locker room! That’s just how guys talk! Not me, of course. But some guys.”

What makes them think we don’t know? In real life I’ve had other men say things to my men I am with, regarding sex, only they think they’re talking in some sort of code that we women can’t understand.
For example, many years ago my boyfriend and I went to dinner with another couple. We went to Red Lobster. The other guy ordered lobster. When our food came he spent about 5 minutes putting butter on it, and mashing it and just whatever. Then he said to my boyfriend, with a wink, “Getting it ready is almost the best part, right Murph?!” Wink wink. I think he honestly thought I wouldn’t get the innuendo.

Why?