Well, as a metal fan myself, I can tell you that metal music is many things, but not cheerful. Part of the music's appeal has always been its combination of heavy guitar riffs and doom-and- gloom imagery.
Babymetal, on the other hand, has presented something unique: the joining of traditional metal-style power chords to idol pop's high-energy, "bubblegum" melodies and performance.
Producer Kobayashi, a fan of such groups as Kiss has cleverly created a mystique for Babymetal in which they are not just teenage girls but messengers of the Fox god, using "metal Resistence" (the title of their new album) to fight the coming apocalypse.
Songs such as "Megitsune", "Gimme Chocolate" and "Karate" have proved to be winners in the global fan base, and elevated Babymetal to star status in many countries...
As with most successful music groups, Babymetal also has their critics who state their songs are not "real" metal, and are just mass-produced along with their image, to appeal to middle-aged male perverts.
The widespread appeal of Babymetal among a range of ages and genders takes the air out of such grumbling, and will probably ensure further stardom for them, at least for a few years... (G.K)
metal music is many things メタルミュージックは色々な要素を持つ
doom-and-gloom imagery 陰々滅々とした心象
on the other hand 一方
as with 〜 〜と同様に
take the air out of such grumbling そうした不平を乗り越える
ensure further stardom さらなるスター性を確約する