I like the show but I have to agree. The fans have become toxic and I couldn't blame the writers for deciding the pay isn't worth it.

I guess the internet can't handle protagonists with seriously flawed personalities. People often treat them like role models, praising their independence, edginess and badassery, while ignoring how these characters make their life worse with their cynicism – a common theme in these type of shows. Rather than trying to avoid ending up like Rick they use him to validate their own shitty behavior. I doubt the creator of the show intended that kind of influence on the fans.
I don't know if R&M requires a certain level of intellect, but it probably requires maturity in order to distinguish when it challenges social norms and when it actually does kind of agree with them.