Sigh. Sadly, I understand why MC and Visa do this. If they are seen to be facilitating people paying for something that the media have taken against as a cause celebre, whether it's the (obviously and rightly) illegal underage stuff that was sneaking onto PH and OF, or just the general vile debauchery that we all like but certain groups that make it their business to try to control what others can see and do go out of their way to campaign about, then they get massive negative PR and maybe sued. Censorship compliance is damage control. The deliberately vague provisio about 'brand damage' is so they can clamp down on new things that have raised the hackles of our various moral guardians before they get hauled over the coals in the media. Imagine if someone watched lots of stepmom porn and then sexually assaulted their actual stepmom and this got into the news... suddenly all step porn is brand-damaging and must be removed.
This puts the banks, payment processors, and sites like SLR into a difficult position, where you can't know in advance what will become verboten, so you either play it super, super safe (like the banks do) or you risk it and then delete all the offending content as soon as it's hinted that MC/Visa is unhappy with some new category of filth.
It isn't 'just the US', of course, but it doesn't help that the US has a comparatively more puritanical outlook on this sort of thing than Europe, because MC/Visa are based in the US and have to answer to the US media, but their policies are global. Maybe our German friends could start a campaign to get their media to make a big deal out of how US companies are denying Germans their perfectly legal smut and see if it works in reverse. But I don't think it will.
My advice, go find all the pervy stuff you want on the clip sites etc and get it now, while you still can. The way this is going I'll be surprised if vanilla porn is even still allowed in a few years, legal or not.
Meh. The world is going to shit and I can't even say 'shit' on half of the internet these days.