actually this is a confusing situation.
The Blu-ray Disc Association is not anti-Porn, But Sony themselves are.
Sony can threaten to pull a manufactures license, But if the manufacture wanted to fight it Sony would lose since Sony does not have final say in it.
There is also the chance that Sony made a threat to them in another area, Maybe Sony is funding the manufacturer or they could be renting the hardware to them for the disc replications, Sony in that sense has pull there as well. Sony did in fact do something to get the manufacturer to deny manufacturing of adult movies. That is true.
The Adult movies in Japan is also a tricky thing as well, It could very well be that these movies were not made in Japan and were in fact duplicated in China. China doesn't need the 'okay' to manufacture movies, once they get the means to make copies then do what every they want. Just look at all the really nice pirated movies you can buy from over there. They look like the real thing, but there a hell of a lot cheaper. Where else can you buy $600 worth of DVD box sets for only $100. Unlike the US in Japan those movies are a lot easier to find in stores so It wouldn't surprise me that the adult movies were made over there. The porn UMD movies were done in a similar way, Japan had them but they weren't made in Japan, The US has 1 adult UMD movie and it too wasn't made in Japan or the US. They can find work arounds but their not always "leget"
What ever Sony has been doing to keep Porn off the UMD could be the same way they are keeping Porn off of Blu-Ray, if they have any really pull in the situation is another story and the only real way to find that out would be for someone to want to release a porn movie on Blu-Ray and then actually bring it to the Blu-ray Disc Association when they are told that Sony won't allow it.