I'm not one to shy away from gore; nor is anyone who has watched enough of this series for the trope page to be relevant to. However, I am one to put in a bit of digression with what I'll tolerate this from. Shock value for shock value's sake does nothing for me. That's the exact reason that so much of what Adult Swim's original line-up consists of causes me to reach for the remote. There's a big difference when it comes to Metalocalypse; despite the fact that the show offers a realistic, and therefor far more intense, take on extreme violence which makes it more akin to an American slasher film than an American cartoon. As horrifying as the portrayed scenes can be, there's real purpose in there.
Metalocalypse is a commentary in nearly every aspect, and this is shown in no better place than within the gallons of blood poured by employees and fans on a routine basis. Despite the fact that it's almost 100% guaranteed that you will be maimed or killed by connecting yourself in some way to Dethklok, people still flock towards them. It is, in fact, displayed to be something to be ashamed of if one calls themselves a fan without sporting related injuries (and if those injuries aren't life-altering in some way). Towards this violence, Dethklok itself fluctuates between complete indifference, sadistic glee, and disgust for those who have put themselves through so much just to be nearer to their music.
Despite being incredibly vocal about their hatred for their fans (the Easter Egg interview concerning fans being the best example, where the members insist that they mean all of the hateful things they say, and then their desire for the fans to mutilate themselves further), people are still willing to give everything for the band, from worldly possessions to their very lives.
This is an extreme example, but such is parody, to the celebrity worship that exists within real society. People are willing to absolve a celebrity of almost any wrong-doing as long as their art form is still strong. With smart enough management and enough talent, even the biggest backlash is pushed to the side if not forgiven entirely.
Metalocalypse warns of the dangers of such devotion; not only with reminders of exactly what mob mentality and hero-worship can cause, but that those who are evoking these reactions rarely care about those who are participating.