>>723853474
They self-imposed it, and now it's ingrained in the American public. Hollywood films originally had tons of nudity. Then the Motion Picture Production Code (or Hays Code) came around in 1930 because they they were afraid that the government was going to regulate movies. When TV came around, the same basic rules were used. Eventually, Hollywood got away with easing up on the rules by using the MPAA film rating system, and figured out that plenty of people would go see PG-13 or R-rated movies with varying levels of nudity, graphic violence, and profanity. But television involved radio wave communication and had to go through the FCC on certain things, so they never bothered to push boundaries there. This is why, when cable TV came around, it became the place to host all the more scandalous content, with some channels even airing hardcore pornography.
Video games followed a similar path, with the ESRB arising for the same reason the MPPC/Hays Code did. There was a big fear that the US government would establish its own rules on video game content, so they self-imposed their own. The internet is now in this stage. Any type of industry-led regulation has proven basically impossible, since it's too easy to just pop up a new website somewhere and web sites in general are extremely cheap and decentralized compared to movie/game studios. So we're starting to see the US government and others start to impose regulations like mandatory ID-collection from porn sites.
If you're asking about "news" broadcasters specifically... well they just love ragebait and companies breaking "rules" is ragebait. People love hearing about "popular company did thing and is in BIG TROUBLE"!