Mainly people bitch about downloading because they cannot get anything on the internet and are not smart enough to use DC++ and SLSK.
Bands barely get any money from their albums. So all those who think they support bands, actually suport labels and distributors. And besides no one to support, metal is dead.
Finally it is all about money. Quite a few metalheads can afford every single record they want.
The other thing is, most people who buy their stuff listen to material that is at most 10 years old. Such stuff is on sale practically in every store and thus is rather easy to get. People who listen to 80's Metal (like I for example) can barely find anything interesting there. Sure there are ways to get oldies, like for example e-bay, but prices there are usually high.