This article goes a long way toward explaining why I abandoned left-liberalism after college.

One protester even brandished a sign that seemed to advocate Bush's assassination. The man held a large photo of Bush that had been doctored to show a gun barrel pressed against his temple.

"BUSH: WANTED, DEAD OR ALIVE," read the placard, which had an X over the word "ALIVE."
...
On Sunday, The New York Times reported that a Democratic congressman discovered that "an opponent of health care reform hanged him in effigy" and was confronted by "200 angry conservatives." The article lamented "increasingly ugly scenes of partisan screaming matches, scuffles, threats and even arrests."

No such coverage was given to the Portland protest of Bush by The New York Times or the Washington Post, which witnessed the protest.

When you consider the relative merits of political philosophies, you have to realize there is a gigantic illusory bias in favor of left-liberalism simply because journalists are overwhelmingly left-liberals and tend to slant coverage as noted above. This is still pretty much the same media that gave Walter Duranty a Pulitzer for reporting how great things were going in Stalin's new socialist utopia, even as the Soviet state inflicted an agonizing death by starvation on millions of Ukrainians.

It isn't just the media, either; teachers in our schools and universities are also overwhelmingly left-liberal and tend to push their ideology on students in the course of knowledge transfer, often unintentionally but sometimes quite deliberately and at the expense of actual education.

The net effect of all this is that to take a realistic view of most information, one has to view it with a very rightward tilt to correct for the left-liberal slant (which explains why Fox News gets more viewers than all other cable news channels combined).

But this is difficult to apply to individual cases where information is missing; for example, given the facts as reported by the NYT, it's hard not to infer that right-leaning protesters are much less civil. It's easy to see why people who avoid right-leaning sources like Fox News develop an inaccurately left-liberal view of the world.