Julian Cope presents Head Heritage

OK, It's pop or metal.

1) It's not very good
2) It's manufactured by the music biz
3) They have metal musicians behind them old enough to be their grandfathers.
4) Are they X - Factor rejects?
5) See 1). It's not very good.
6) Are they being exploited
7) The are nowhere near SHONEN KNIFE
8) I rest my case!

1) Subjective, innit.
2) If said music biz isn't churning out schmaltzy ballads, but willing to draw upon any number of supposedly uncommercial, idiosyncratic elements, instead of presupposing that the public likes its product safe and flat, I'm cool with that particular biznezz plan.
3) I don't recall seeing a rule saying that all musicians have to be exactly the same age (or, on a stretch, born within two weeks of each other).
4) There's something in Japan called Idol music, which hails back to the late '70s. On the surface, it seems to be a Monkees/X-Factor sort of thang, but many of these groups have been encouraged to exercise their weird side, or have latched onto some strange, inspired bit of non-Eastern arcana (reason why that Liverpudlian group, Big In Japan, named themselves that, and that final scene in Spinal Tap), and utilise them in a way they never were in their home country. There are saccharine examples of this music, but most of what I've heard has been full of élan and sprightliness.
5) See 1).
6) Hell naw. There are some savvy fucking kids out there in Japan. Maybe the producers are pushing some of the older genre mash-ups onto them, but it seems all the singers in these videos and albums love what they're doing. There's a concept in Japan called Tatamae and Honne. These are the Public Self you show to other people and strangers- which in Japan's case can sometimes seem practically catatonic- and the more feral private expressions. Compartmentalizing these two sides (which I'm sure the English in particular can relate to) has resulted in some really crazy artistic outpourings from Japan. These girls are getting to express their Honne side the way they never would elsewhere.
7) I like Shonen Knife well enough. They're the female Ramones, right? But they're one of the most Western-friendly groups to come out of Japan. Straightahead guitar-drums-bass-vocals with minimum production. They do not have that little sprinkle of magic J-dust which so much of Nippon's output is overloaded with. I think it's a little ugly how a barefaced imitation of a Western band is s'posed to supersede all else from Japan. (I will admit, I prefer their first two albums to Babymetal, but they still come nowhere near the best J-Pop I've heard).
8) It seems a bit like your case was, "I don't like it ergo no one should". As to Babymetal, it took me a fair bit of time to warm to them, as I can't stand those turgid metal guitars draining the life out of anything they grace, but the hooks shone through. Plus, their album isn't all metal at all. I even recall a bit of cod-reggae on there (though it's better than that sounds).

I genuinely love Idol Poppers Bis's collab with old-time Japanese Harsh Noise vets Hijokaiden, Bis Kaiden. It was one of my fave releases of last year. Here's their Jun Togawa cover: https://www.youtube.com/watch?v=rjVT-jsiPnw

Japanese coolness, just like Babymetal. :)