Nah you're not a poser.
I'm kind of an outlier, since my tastes range wide across the genre. Even with a lot of my metalhead friends on another forum I go to, there's only one dude I know that lists more bands I've never heard of. (That'd be because of the age he was when Thrash was king)
I always say that since the genre as a whole (1969 is the agreed upon year by most) has been around for 50 years, there's a lot to catch up on xD
Dave Mustaine is my hero. Love his conspiracy fueled lyrics.