It's one of those things that just embedded in pop culture now. Yes, it was ugly. It's been surpassed in ugliness by Cubes and Elements and Smarts and Scions and that grotesque electric thing from MItsubishi, but the Aztek still gets mentioned all the time, long after being out of production.I know. Everyone's favorite whipping-boy. Like the Cimarron. There was nothing mechanically unreliable about the Aztek. It also received one of the highest satisfaction ratings from owners in its day.
Even funny jokes aren't funny anymore when they're just beat to death. I think it's the unoriginality of the never-ending Aztek jokes by very "clever" people that's really annoying.
Another one is the Camaro/Firebird and mullet jokes. I can assure you that after three Firebirds and a Camaro, I've never had a mullet. Nor did most people who ever bought those cars. There's been funny stuff on SNL about this, but then people not bright enough to come up with something funny of their own just run with it and beat it to death. This one particularly is annoying to me because it did much to destroy the image and reputation of these cars and I think partly led to their demise back in 2002.