It's called "The Crazies" and it doesn't limit itself to men, women, blacks, whites, Conservatives or Progressives (it does, however seem to affect a larger percentage of Greens than normal). Symptoms of "The Crazies" can be as mild as talking to your shoes for companionship to a more severe case that can include shooting up a school where you didn't get tenured, or turning yourself and a lightweight airplane into ballistic revenge against the IRS.
Side effects include people latching onto the affected's politics and trying to use that as a bludgeon against their foes, as if every member of that group managed to catch a case of "The Crazies" at the exact same time.
The recent school shooter was an extreme lefty who adored Obama. This does not mean Obama supporters are murderous, non tenured, teachers. Some dude just played a game of human lawn darts with an IRS building and his rants are bugnuts crazy, but many of his gripes are anti-government, anti-taxation.
The difference, of course, is you won't hear much about the school shooter's politics, but The Man Who Treated the IRS Building Like His Own Private Landing Strip? I assure you he will be played as a Tea Party member (they'll just leave out all the nods to communism and the GW Bush hatred).
*Sigh*