Opie and Anthony
I think I can answer that question for them.
First, it's not just radio. Remember Bill Maher? (Don't worry if you don't; he's pretty forgettable.) His crack about our military being cowards cost him a TV show. Going back further, remember Howard Cosell? Jimmy the Greek? Rush Limbaugh? They all made comments of varying degrees of racism on television shows,and they all were punished for it. Limbaugh was fired. The Greek was banned from TV.
Here's what it's all about, you morons. You crossed a line. You aired an extremely offensive bit of "comedy" guaranteed to anger just about anybody with any sense of decency, admittedly a shrinking minority, then to compound that error, you defended it by minimizing the seriousness of the offense by calling it "entertainment," and then indulged in juvenile delusions of persecution instead of admitting you screwed up.
And you did screw up.
Let me give you another example; while he might think it's funny and entertaining to tell racist jokes all day long, a corporate executive won't keep a job long if he does, regardless of whether he's in radio or not.
It's just that simple.