If you look at the timing of these decisions, it's pretty clear that that yeah it's risk based, but the risks are political. It's only a week between this op-ed calling on the credit card companies to drop Pornhub and them following through on it. https://www.nytimes.com/2020/12/04/opinion/sunday/pornhub-ra...
There was a flurry of congressional bills specifically citing that article at the time. (Here's one for example: https://www.businessinsider.com/bill-introduced-criminalizin...) I can't find one that specifically threatens the payment processors, most go after the sites or their hosting providers, but the payment processors probably had the sense to realize they were in the blast radius and that it was best to pre-emptively self regulate.
There was a flurry of congressional bills specifically citing that article at the time. (Here's one for example: https://www.businessinsider.com/bill-introduced-criminalizin...) I can't find one that specifically threatens the payment processors, most go after the sites or their hosting providers, but the payment processors probably had the sense to realize they were in the blast radius and that it was best to pre-emptively self regulate.