I think the most common reason, though, is that guys have learned their dirty-talk from porn, and some porn is not as good at dialogue as others. Some is flat out degrading, and only a few women enjoy the talk going that far.

For example, the phrase “Oh God. You’re such a (noun).” There are plenty of nouns that will excite a woman, but there are also plenty that will hurt her feelings. We, being stupid men, do not know the difference until we try them. So it’s just better not to risk it in most cases. Cuz once you hurt her feelings in the heat of passion, you can write off any further encounters for awhile.