I wasn't around for it, but I've heard that a large reason for the dying of the "free love" movement was the arrival of HIV/AIDs as a serious disease in America- especially when little was known about it. Much of the complaint is based on ideas of sex being some important thing to be done in only committed relationships. If STDs have a role in that view of sex, then it is slightly relevant even if it was just by giving those who want to shame (female) sexuality an excuse to argue with.