It has vague referential humor that appeals to normies and makes them feel smart when they understand certain jokes.
Beyond that, Rick is a cynic, which widely appeals to the preferred mindset of both the audience and population managers alike.
The biggest part, I'd think, is the correlation they feel with themselves and Morty and their desire to be saved by a reluctant man with competence, Rick. The dynamic seems to inspire their cynical and apathetic lives.
Let us not forget those who identify with Rick's desperate desire to not give a shit, and his failure to realise that goal.
Yeah, that's another great point. He always ends up saving Morty/his family despite his reluctance.
And high-energy cartoon violence, which is a more artistic version of shiny objects.
(post is archived)