I have no problema with the riffing argument they have.
I do weekly updates yo muy library finding new albums and bands all the time that are just forgettable "guitar-noise".
Metal has come through some dark periods where every new band seemed like a rip-off of another well established band, and for some, innovating in metal is just making noise.
Some of it is quite creative, actually, like Igorrr, but other Like Z&A is too varied.
Sometimes it annoys me not finding some pseudo-metal band I discover but I don't have a grudge with them even though I've been called out for being a corpse meddler in the forums (reviving very old posts).
There's another database, Spirit of Metal, I think, that isn't that picky. But for what MA is, I salute their stand, especially through times where we might see Miley Cyrus or any other pseudo-artist identify as a metal act and to be "included".
Basically you need to be able to express your ideas simply, avoiding SE jargon as much as possible, and state how stuff either makes money or saves money.
I don't find Zig nearly as readable as my D code, but alas, I don't do systems programming.