Source?

Wouldn't be surprised, metal fans tend to be pretty dedicated.

https://i.postimg.cc/ZRnZLgkm/global.png

via Spotify Insights

This is globally, but it tends to vary from country to country. Hip Hop ranks highest in Norway, for example.

about metalheads' loyalty i d its hardly suprising....

where i m from metal was pretty popular in the 90s,you could see it literaly in scools and downtown. but nowadays teenagers in metal band shirts are a total rarity.

theres still big interest in metal concerts but from people >30years old..

i like a few white rappers: aesop rock, el-p, the guys from cLOUDEAD, sage francis, 2maybe 3 albums by buck 65. most of those things you could tag as nerd-hiphop i guess and i also guess that their social impact is next to nothing [i could probably exclude el-p?]
and...ok, usually they suck.
on the other hand good white (many times instrumental) hiphop producers are not that rare..

"hip hop popular to "rebellious" whites for the same reason blues was"
seems to me that the above phrase is mostly true but then again i have a distant view of whats happening in the us, even western europe. and that view is probably distorted by the media i like to keep up with sooooo i dunno.

Drake's black, son.

Even Obama is blacker than Drake tbh.

Drake's from America though.

So was Elvis.

And what is this "worst approach to music"?

The unholistic, 100% formal approach that school bands teach where things like improvisation, individualism, and playing with passion are alien concepts.

EDIT: I don't think that music theory is without value btw, I just find the current model that I've seen in American schools to be overly limited and more restrictive of artistry than anything.

Assuming people are creative and can think for themselves, I'd say there's nothing wrong with getting a foundation during school years. Now, if you go to the conservatory and learn to become a complete robot and then go on to form a prog metal band, you may be lost forever.