The idol culture is extremely unhealthy. This is objectification turned to 11. They get a pass in the US because it seems so distant and Japan is "odd and cool" but it is actually really creepy.
Fans like those stars for their whole package (myth, personality, songs, artistic expression, style, etc) not e.g. just for their body (which is usually implied by objectification).
It's also not much different than our pop idols, especially of yore (up until the 00s or so, before several other occupations, such as games, social media, web surfing, selfies, and tons of higher quality TV and movies) basically replaced pop music as the major obsession of western kids.
There have been idols attacked (and even murdered) plenty of times in good ole US.
0 - https://en.wikipedia.org/wiki/Japanese_idol#Fan_culture 1 - https://en.wikipedia.org/wiki/Japanese_idol#Criticism
I also wish people stop considering their country's morals and current fashions as the yardstick to measure the whole world...
(Especially if they don't have such a great, past or present, track record even by their own standards, to begin with).
Who are you to give or give not Japan "a free pass"? Who said Japan needs a pass from outsiders?
To quote Feyman:
"The next morning the young woman taking care of our room fixes the bath, which was right in our room. Sometime later she returns with a tray to deliver breakfast. I'm partly dressed. She turns to me and says, politely, "Ohayo, gozai masu," which means, "Good morning."
Pais is just coming out of the bath, sopping wet and completely nude. She turns to him and with equal composure says, "Ohayo, gozai masu ," and puts the tray down for us.
Pais looks at me and says, "God, are we uncivilized!"
We realized that in America if the maid was delivering breakfast and the guy's standing there, stark naked, there would be little screams and a big fuss. But in Japan they were completely used to it, and we felt that they were much more advanced and civilized about those things than we were."
It's all of the downsides of a celebrity multiplied by 10 and no to much of the upside. The company controls how they look, what they say, who they associated with, their entire creative output, everything. They get treated more like breakfast cereal mascots than actual living human beings.
Except lots of money and fame and a fun job...
The fame and fun factor are certainly a big reason why people willingly do it, but that's about it for compensation.
President Reagan was shot by a lunatic obsessed with actress Jodie Foster.
Sometimes I think the Japanese are attracted to the idea of their exceptionalism.
For many teen musicians and actresses, they are generally marketed towards fellow teens. The fact that adults focus on them is incidental (IMHO).
That is not necessarily the same with certain Japanese niches:
Especially when you add the world of "junior idols":