Because everyone knows the less you know about what you’re doing the better it is.
In case anybody is unfamiliar with the books he’s preaching against, Tim Lahaye’s book The Act of Marriage has historically been pretty much the one and only sex ed book for fundy married couples. It basically contains a few pages of clinical descriptions and some confusing diagrams followed by 987 pages of instructions about stuff you shouldn’t ever do.
If that’s too much information, one has to wonder what kind of education this preacher would find acceptable. Perhaps this set of LPs??