FWIW Mastercard are simply lying, as anyone who has ever had to touch adult payment processing will tell you.

There's even a (non-public) list of keyword banned terms.

Indeed, and the keywords are vague and they refuse to rigorously define them. Adult payment processors just run around in the dark until they trip over one of these landmines.

Even the (rare) categories of content that have been legally determined to be non-obscene (e.g., werewolf erotica [1]) can fall under banned keywords (in this case, “bestiality”).

It’s a stupid extralegal system and ought to be destroyed.

[1] https://time.com/archive/7118599/california-prisoner-fights-...