What other people are saying is probably true to an extent, but also consider that algorithms often end up artificially inflating the popularity of certain beliefs: young people who act like 70s religious grandmas might be a tiny fraction of the youth population, but if they're made to click on things that will offend them and make them comment in droves, that generates a lot of engagement. If people end up arguing with the pearl-clutching teenagers, that generates even more engagement. And the false impression that Satanic panic is a popular idea among young people happens to be a convenient side product for those who stand to benefit from creating that impression.

If nothing else, I've got a goth zoomer cousin, so I can at least attest that they still exist.