What I see is an increasing pattern of right-wingers using the dregs of society (low-brow comedians, shock-jocks, degenerate rock stars - I'm looking at you, Nugent) to give themselves "street cred" among a certain set of voters.
Old-guard conservatives like wealthy industrialists and elitist snobs - the William F. Buckley types - cannot appeal to the demographic that the conservative movement now depends on. So they have increasingly made a devil's pact with degenerates whose political motives are beyond suspect. Ted Nugent, for example, isn't really a conservative in the Goldwater/Reagan/Buckley/Kirk sense. He probably has no clue who William F. Buckley and Russell Kirk were, and would punch them in the face if he met them. He's also a philandering, amoral, vulgar hedonist who is the antithesis of everything that the moralists like Buchanan, Robertson, and Falwell stand/stood for.
However, the Ted Nugents and Larry the Cable Guys are attracted to the Right simply because the values of the Left - equality, inclusiveness, feminism, and progress - are so disgusting to their little reptile brains. Not because they are actual conservatives.
So, having enlisted these morons in their quest to appeal to blue-collar male voters (an insult to good, hard-working blue-collar men, I might point out), they have allowed this knuckle-dragging, thuggish mentality to infect the right-wing message in general. The Right has become meaner as a consequence. Thus polite discourse has given way to death threats and the like.
