The validity of Harvey Weinstein’s argument lies in that double standard that Tim Winter and the PTC mentioned earlier, which is the double standard Weinstein implies rules the MPAA.
Weinstein especially fought that battle with both Philomena and The King’s Speech, where the levels of choice profanities exceeded the MPAA’s allotment of profanity in a PG-13 film, automatically classifying both films as R-rated products.
That standard is, naturally, the one that allows violence more leeway to make its way into PG-13 films, but shades a film with any sort of content deemed “controversial” to groups like the PTC with an R-rating.