I know that not everyone like GG Allin. I'm sure I wouldn't like his live shows; because I'm not into smelling feces. Others just don't like his music but I do.
This article talks about the later GG Allin. There is a certain mythos that he created about himself. This was all marketing. He got on Geraldo; he was on Springer... his whole schtick was about drawing attention to himself and his music.
He only started flinging shit in the mid 80's. You can say that people weren't interested in his music. He was addicted to Heroin and needed to make money somehow... so he created this onstage persona.
Anyways, I like his earlier music. It sounded closer to punk and less hardcore.