A little more punctuation would have made it easier, and it took me a little while.

Once it finally clicked for me, I actually found it an interesting point I haven't heard before. That the main cause of the satanic panic was a fear that world-building becoming too popular would expose the likelihood that Christianity was also a fiction.

Personally, I think I find the idea more interesting, than I find it convincing.

I think it's read like this:

>The whole D&D vs Christianity vs Tolkien mess of the 90s grew on this inability to tolerate fiction that proves that anyone could invent your life-ordering fiction.