Don't get hung up on the morality bit. The point was that The Pill changed behavior.
So what?
So there's a value judgement about whether that change in the behavior of others is a good thing. So "morality" which is where this came in.
You want to make cases about the pill adoption and STD prevalence getting worse, go right ahead. It is different data and a very different case to make. Also far from obvious which way it goes, fwiw.
>So what?
It sounds relevant if the pill was introduced and got legalized on the grounds that it would not cause that kind of change but e.g. only help married couples to plan their pregnancies.