The worry about a hard-coded list stems from Lemmy itself doing exactly that several years ago. And then when pressed, the response was:
If you dont like it, fork it. Stop bothering us about it, we will never fully remove the slur filter.
To be fair, after a huge outcry the Lemmy devs did eventually relent and removed the block. Yet somehow on hexbear and lemmygrad (see links to those in the context to this sub-thread above), Lemmy has never done anything wrong, and PieFed can never do anything right.
That's enough reason right there for me to leave Lemmy behind. Thankfully PieFed exists or else I'd have to leave the Threadiverse altogether, and yet there will always be some who bring their false arguments around the defederation filters.
Since that time btw Lemmy has added an additional hard-coded filter that highly ironically - and hilariously to me - went even further towards propagating community lists, even while PieFed has significantly walked back its own such efforts in that regard. Not that they would ever acknowledge either of such, of course:-).