IMO the only serious problem with social conservatism is when it's legislated. Accordingly, feminism was at its best when it was about liberation. Touting sex positivity vs touting traditional gender roles are on equal moral ground, and it seems to me as though you're looking to make a case against unmitigated sex positivity, while feeling as though this means you're necessarily looking to roll back liberation efforts. So long as the case is about "oughts" rather than "musts," I don't see the problem with you making whatever case you want.