Why is G. Gordon Liddy controversial?

According to Wikipedia:

During Liddy's tenure as a radio talk-show host, many controversial statements have been attributed to him, including causing the release of John Dean's home phone number in 1993 on the radio when Dean was threatening to sue Liddy for defamation[citation needed] and Liddy called Dean's home on the air to only reach his answering machine that announced the phone number.[citation needed] Some of his comments led to condemnation by then President Bill Clinton[citation needed] who was under constant attack by conservative talk radio.[citation needed]

* August 26, 1994 - Now if the Bureau of Alcohol, Tobacco and Firearms comes to disarm you and they are bearing arms, resist them with arms. Go for a head shot; they're going to be wearing bulletproof vests." ... "They've got a big target on there, ATF. Don't shoot at that, because they've got a vest on underneath that. Head shots, head shots.... Kill the sons of bitches.

* September 15, 1994 - If the Bureau of Alcohol, Tobacco and Firearms insists upon a firefight, give them a firefight. Just remember, they're wearing flak jackets and you're better off shooting for the head.

Liddy claimed that his detractors omit some important context: [8]
“ I was talking about a situation in which law enforced agents comes smashing into a house, doesn't say who they are, and their guns are out, they're shooting, and they're in the wrong place. This has happened time and time again. The ATF has gone in and gotten the wrong guy in the wrong place. The law is that if somebody is shooting at you, using deadly force, the mere fact that they are a law enforcement officer, if they are in the wrong, does not mean you are obliged to allow yourself to be killed so your kinfolk can have a wrongful death action. You are legally entitled to defend yourself and I was speaking of exactly those kind of situations. If you're going to do that, you should know that they're wearing body armor so you should use a head shot. Now all I'm doing is stating the law, but all the nuances in there got left out when the story got repeated. ”

Additionally, when Liddy spoke about listening to Hitler on the radio, he stated that it "made me feel a strength inside I had never known before. Hitler's sheer animal confidence and power of will [entranced me]. He sent an electric current through my body." [9]

McCain proud of knowing Gordon Liddy

Today on David Letterman show John McCain said he was proud to be a freind of Gordon Libby.

At least "he's not paling around with terrorists". Only men who propose the killing of sworn officers of the United States of America!