The toxins as you so suggest are a different matter altogether vis-a-vis birth control and the Catholic Church, which can however be extended to say Jehovah’s witnesses or Christian Scientists with regards to medicinal drugs and procedures as a whole.
The moral line between between birth control and abortion is quite clear at least to me, but then it is line anchored at both ends by people stuck on absolutes.
Again though back to the thought that taking sexual and marital advice from a celibate is counter intuitive.
though they may be right on certain things, it’s only serendipty rather than something you can attribute to wisdom and experience.
Back to the aside ... by relative time frames, we are like the Romans and the low birth rate western worlds will be swallowed by the high birth rate third world.
That's an ad hominem argument; almost a textbook case of one.
It might make a tiny, slim bit of sense if the "celibate" in question were making up something out of whole cloth. In this case, though, he's just reiterating for you what had been the constant teaching of the whole Christian community up until 1930. It doesn't take any special understanding of marriage to do that.
There are also plenty of married people who will tell you that artificial contraception is a bad thing. Does their opinion not count?