Why is there such a nudity taboo in the USA?

I was just watching this show on one of the main German channels that had a 15 minute coverage on saunas. And even though it airs at 8pm they had no trouble showing a model being completely naked in the sauna and then even showering and applying lotion to her body. And I have seen things like this many times. It's not a big deal. But I can't even remember any mainstream USA show trying something like this. They seem to avoid showing women's breasts at all costs. Brutal murders no problem. Women's breasts never.

Why is this? I mean I get the conservatives have a big influence in the USA and they have some serious problems with sex but why are TV companies tolerating this? And why are people tolerating this? It seems wrong