It depends on what you mean by "the problems". As I said, copyright issues have often been used as stalking horses and copyright holder used as cat's paws, where the grudge or "problem" was the porn but the excuse was the fanfic.

So for instance, I've talked to people about a variety of incidents in the 80s (one involving George Lucas, IIRC) where Fan A hated Fan B's porn, so Fan A wrote to the copyright holder, saying "Look there! Unauthorized use! And it's porn!" -- because the legal basis for attacking porn is slim, but copyright violation is legally clear-cut (by comparison).

So yes, the *problem* is porn, but the *excuse* is copyright.

Am I being clear?