This explanation strikes me as being closest. There is a well known problem, which is that using the non-crypto payment systems for things is difficult, by disintermediating the payment provider from the product the paidlink guys can say they have clean hands.
VISA: "What are you selling?"
PL: "Links"
VISA: "Links to what? Prohibited items?"
PL: "Oh no, our TOS doesn't allow that, we tell our customers not do do that."
VISA: "Can you verify that they don't?"
PL: "Uh, well as far as our platform is concerned their just links, you know like groceries are just groceries, we don't get into the nitty gritty of what exactly they are."
The weird thing is, even if the PL guys are 100% aligned with not letting their customers use this for "bad things" their customers are going to try to find ways around any systems they put in place to check or regulate.
Watching the shenanigans people pulled to get around our efforts to prevent the misuse of Blekko (a search engine) was really educational in that regard.