Because it's not actually played for laughs
you have to a) be able to spot the deadpan jokes and b) know just how ridiculous the world of heavy metal is. Which helps with a).
(Bazongaloid, Wed 22 Jun 2011, 9:40, 2 replies, latest was 15 years ago)

I'm sure I'll watch it at some point

( Agnostic Antichrist Baltimora, Wed 22 Jun 2011, 9:43, Reply)

I read somewhere that Liam Gallagher didn't realise it was a spoof.

( Monty Boyce, My cheese game is strong, Wed 22 Jun 2011, 9:44, Reply)

I like the fact that Ozzy Osbourne
actually did have a giant stonehenge backdrop during the late 80s.

And he had a dwarf who dressed up in a devils costume and jumped around on top. He used to nickname the Dwarf Ronnie.
(Bazongaloid, Wed 22 Jun 2011, 9:46, Reply)

Hahaha that's 'Midlands wit' for you.

( Monty Boyce, My cheese game is strong, Wed 22 Jun 2011, 9:52, Reply)