It has a level of appeal globally, but not enough to be mainstream most places.

E.g. the top Norwegian death metal bands are amongst the most successful Norwegian musicians ever, yet they don't sell much at home. Yet they do extremely well by Norwegian standards because they sell ok all over the world.

It's mostly a male, working class dominated genre in terms of audience, so it's ignored and ridiculed for not being glamorous enough to fit mainstream media's mindset.

That's a good thing because they would slowly change it if they got their hands on it. Sony buying Century was disappointing but there's alternative labels. Metal should stay underground to protect itself from the people who see it as 'weird'.

I was wondering the same. Does "weird" in this instance mean that the phenomenon does not begin from marketing departments of large IP owners?

It's weird if all you know is pre-packaged mass-consumption pop music

It's literally like they are fulfilling the Portlandia "Weirdo's" sketch: http://www.hulu.com/watch/758287

That headline is saying it's the global appeal that's weird - not the 'something'.