The issue has never been that the adult industry balked at dispute fees. PSD2 enforced two-factor payment checks also make disputes much less of an issue. This is entirely about Visa/Mastercard simply refusing to work with some industries.
That's a lame excuse tbh. If they had no objection they'd allow it for every merchant and then only after said merchant has a lot of "disputes,etc" would they then block said merchant from selling such services. They even have a genuinely good reason then!!
It's like saying "yeah we don't service the entire Chinese and Russian IP block because of risk and lots of hacking coming form there."