Entertainment has no shortage of violence, gore, drugs, alcohol, swearing and romanticizing/downplaying straight up murder and other crimes. But when it comes to sex there's an... interesting mindset.

-You can have characters clearly having sex as long as you don't show too much anatomy
-Butts are fine but not penises or vaginas
-(For anime especially) You can show the entire boob but not the nipple
-Male nudity is funny but female nudity is rare and immediately labed as fanservice

There's more but you get the point. I've thought on this for a while but the straw that broke the camel's back was when I was watching a show about mob bosses that was cool with talking about murder and drug deals while dropping F bombs, but censored a drawing of topless women. :\

It's very much linked to where said show/movie is produced and the cultural sensitivities of the region.

Because plenty of European-made movies don't have the same stigma when it explicitly comes to nudity and sex. The reality is though that European movies don't get the same level of viewership, often due to language barriers, barring English of course. Whilst I do agree there is a double standard, the constraints often come from the broadcast networks themselves and are concessions shows/movies make to get airborne. That has since gone away to a degree with the move to private networks and streaming platforms, in part thanks to the success of HBO television. Of course on regular TV, those rules are still very much enforced.

It's also very important to consider the amount of media produced in one's country, as the US exports an insane amount of media abroad, and in turn, elements of its culture that are embedded in said material.

For Japan and anime, it's very much because anime is on network TV and thus will adhere to the network regulations, less they end up on some dodgy hentai channel with lower than average viewership. Of all these particular styles and pieces of media, anime by far will be the last to change due to Japanese culture both when it comes to traditional values and business practices.