I think it might be because Japan might be a little bit conservative about things, like they constantly change terms for things like Deaf and other disabilities to make them lesser impacting, the Sex might just be because it's simply THERE, but they don't want to actively bring it up....it's probably some ingrained cultural thing in there somewhere, not something specifically about Sex but how they go about broadcasting it; ie it's simple to show, wave and even shoot a gun on screen, but stuff such as rape and whatever are toned down to TV-appropriate media from original things such as Manga, blood is OK, but appears to be heavily censored....seems to draw the line at decapitation though, but that might be some ingrained stigma or possibly it was too close to a potentially infamous murder case, perhaps?
The whole thing with Tentacles might just be because of westernization following WW2, despite the war affecting a lot of people, it did open up communications with other countries whilst also providing new things in the field of medical science (heard somewhere that some countries escaped war crimes by contributing their findings as a social thing to enhance things) they had to look ultra decent to westerners which meant that they had to blur things such as penises and whatever, though tentacles were fine...
...though to be fair, Tentacles may have been culturally artistic even before WW2 anyway, doesn't really mean a whole country is like that though, there's more to Japan....tons of regional differences and stuff, would be amazing if they had some common thing in the past.
