Well, even some well intentioned people like our host don't seem to care about exploring metal at all, which is quite sad, especially for those who genuinely like music. The thing is that saying "I don't like metal" is like saying "I don't like electronic music", it's just wrong, everybody likes a bit of Alphaville or Depeche Mode, same way that I've yet to encounter someone into music who really dislike Black Sabbath.There are people on this site who are such productive contributing members most of the time, but something comes up and they can't help but disrespect everyone else for no reason. It really grates on me. You don't get it? Cool. Move on and stop wasting everyone else's time with your ignorance.
I'll probably make some people sneer, but I claim that extreme metal as a whole is the popular (as in not classical) genre who went the furthest into experimentation and creativity, becoming in the process completely inaccessible for the profane and maybe the reason this stereotype exists: you just CAN'T go from AC/DC and Witchfinder General to Bethlehem or Demilich and expect to "get it", you simply won't. You need some gateway drug like melody or rhythm oriented subgenre variants before (maybe) getting to the esoteric stuff; something like Amorphis, Gehenna or Blut Aus Nord's melodic stuff.
I guess being a musician or having a state of mind compatible with the music can also help big time.