According to this piece in Buzzfeed, one of the Boston bombers was a listener of Alex Jones' radio show. That show is known for peddling conspiracy theories, and a few of those allegedly contributed to the bomber's radicalism. Alex Jones was interviewed by Buzzfeed about his famous listener, and he was completely unconcerned about this development. He didn't pause for even one second of introspection. Then, of course, he used it as further proof that the government is out to get him. Obviously this whole bombing is a government conspiracy to get people like him to shut up.
Reminds me of the days after the Oklahoma City bombing. If you ever listen to those Timothy McVeigh jailhouse interviews, you'll discover that he was a die-hard listener of right wing conspiracy talk radio, and his concern at the time was that the government was coming to take away his guns. It had to be true--he heard it on the radio. The same was true of that Pittsburgh killer. These are mass-murderers who were influenced to kill people because of what they heard on the radio, and the hosts that said those things were not even disciplined or asked to tone down their rhetoric.
Look, I understand that the First Amendment gives every citizen the right to say whatever he or she chooses to say. It doesn't give them the right to say it on the radio, however.
It's the radio stations that consciously choose to air these shows, and the adverstisers that consciously choose to pay them money, that should be ashamed of themselves. Just because it's legal, doesn't mean that it's right.