[altendo]

I believe that it's an assumption for now, but a reasonable one to make. I think it's unlikely that Visa exposes itself to legal risks where MasterCard is not - why give your competitor an edge like that?

[amanaplanacanal]

That assumes that there actually are legal risks, and that there isn’t more money to be made by continuing to process these payments.

[dageshi]

For Mastercard and Visa the money to be made is a rounding error on a rounding error, there are lots of other industries that don't have the same PR risks as adult content does.