Unlike ICP, GWAR isn't getting paid by a second tier beverage manufacturer to roll a cheap brand of soda into their image. If they were, they'd at least have a sense of humor about it. They wouldn't just pour it on their fans while hypnotically repeating the brand name.
Faygo actually hates being associated with ICP. They want to be a "family" brand. But you're obviously not going to see them complaining when ICP is buying semi-trucks full of it.
I went this year. I was waaaay back because I don't like ICP that much. I went because it was an important thing for the whole Gathering thing. I actually did have fun at the gathering, despite a few assholes. Juggalos aren't bad people, just... Very insecure about who they are or should be.