It's not that bad of a joke. I know some of their writing sucks but that joke works pretty well. Just because Matt and Trey rip on them doesn't mean everything they have ever done turns to shit. Now the Cleveland show on the otherhand...
I thought this was funny. I like how Brian is supposed to be an intellectual yet fails to maintain himself when he sees his reflection. Peter, obviously a complete moron, just fails repeatedly. It works. Seth McFarlane is no dumbass.
That being said... SPELL-CHECK FFS.
Yeah, this show isn't for high school turds. Although I was once a high school kid... I wasn't a turd and found this not funny as well. As I grew a few years older, it became much better. I like this show right now.