To start, I really don’t have any idea how seriously ICP takes themselves. For you to really embrace everything they advocate in their songs would be difficult, and mostly unpleasant. They have four primary foci in their songs:
Sex with fat, unattractive women. They return to it again and again, with special attention on how indiscriminate they are in their sexual liasions, and the faults of the women in question. This can get grotesque.
Killing people. This can get truly grotesque, as they go into methodology and gore-flecked detail with undisguised relish. There is generally little talk of shootings, with hatchets being a preferred weapon.
Outcasts, of all sorts. They style themselves as sort of ultimate outcasts, in terms of birth, life, school, and their professional endeavors. Song after song about how strange they are, hated and friendless, disliked by the advantaged kids at school, on and on in that same vein. This alienation, I think, is at the heart of all of their music, inextricably woven into basically their entire stage persona, and would make an excellent paper or five for some aspiring sociologist (or psychologist, or whatever appropriate discipline.
An odd invented mythology surrounding the “Dark Carnival,” from which stems their stage makeup and Insane Clown act. This also ties back into #3, the whole alienated freaks schtick. Though too convoluted and inarticulately expressed to go into here, they have a fairly complex bit built up around the arrival of characters from this circus (through album releases) building up to some final brouhaha.
When taken all together, this is a really surreal mix, and it’s technically impossible to take it all seriously. Some of their earlier work does indicate that this stage persona thing has been steadily built up, and become more sophisticated. What kids buy into is the sense of rebellion behind it, rebellion against that alienation. I think the fans get a kind of resonance rather than serious belief- these are fantasies in the Big Rock Candy Mountain vein, not the “Gee, I wish I had a Corvette” vein. “Getting it” in this case involves understanding what that kind of angst and anger stems from (and multiple head injuries can help with that), not taking it seriously. I think most people, including a minority of fans, just don’t understand the underlying theme. A lot of alienated, geeky adolescents do, though, and many people who grew out of that still get the joke and dig the tunes.