"There really is no slippery slope -- if there were, then the world would have ended years ago. As it is, there are only trends that come and go..."
When, in this nation's past pray tell, was dry humping like dogs in a back ally the trend? What past trend do you suppose will be the next generation's form of rebellion to replace simulated copulation on a dance floor?
You assume a type of moral entropy that doesn't exist. A lot of other factors play into it, such as economics, technology, geography, demographics, etc. etc.