Misogyny? I don't know about that. But singling out sex as a restricted topic displays a hugely skewed sense of priorities. At least in the case of the MPAA ratings, misanthropic even, if you consider the implied comparisons and rankings (beating someone is more acceptable than having consensual sex with them?). To avoid associating ourselves with those "values", I'd be very happy we refrained from using the MPAA's terms (don't they have those trademarked, or something? I thought I remembered some controversy).