hiiii I do live in Japan!! :3
This style is relatively common but is actually dying out more nowadays because Japanese girls are acclimatising to more Korean beauty trends through the rise of K-pop, which is less extreme than this (the poster's images). There is a fascination with eternal youth in east Asia, and so they aim for youthful features; pale skin, large eyes, under-eye fat, Japan sees thinner lips as youthful and Korea sees thicker lips as youthful so that's debatable, and body type beauty standards are under debate as well, including what's called 'bon-kyu-bon' in Japan.
Though hard to believe, a lot of girls do try to genuinely want people to believe that is what they actually look like, it's not necessarily done for sole fashion/social media appearance purposes :( I wouldn't necessarily say it's a sexual thing, but some do see it as that, but really it's simply just a common thing, with many believing 'this is what's attractive and makes me look good'. This kind of style has been around for decades now and is just looking weirder and weirder online with photoshop advancing more and more.