Unfortunately in this echo-chambered modern world, it is very easy for lies to be layered upon lies and built into a seemingly-reasonable truth. This is done over and over again by those who are always willing to put their self interests above the common good. They are also cowards unwilling to stand up for their mistakes and take their medicine. It's much easier to go to their issue-friendly echo chamber and say whatever they want to say because they know it will be supported by more lies and more lies, and believed by those who want to believe their side, until it becomes this massive entanglement of lies, half-truths, lies of omission and cherry-picked facts that not even the smartest and most dedicated person could untangle it.
It also means that it's very difficult to counter this nightmare with simple truth. Put forth the truth in the form of facts and they'll counter-offer their own cherry picked facts. They're willing to go further than you because they have more on the line -- their character is at stake -- whereas all you have going for you is truth; and that's a heavy, burdensome thing to carry around. It gets very tiresome banging your head against the wall; doesn't it? It seems as though they'll never get it.
This excellent article by Barry Ritholtz in the Washington Post, "What caused the financial crisis? The Big Lie goes viral," attempts to fight back against that echo chamber on the topic of what caused the financial crisis of a couple years ago. You can sense his frustration in having to point out the same facts yet again that everyone should already know (and probably do if they were willing to examine it honestly.)
This political cartoon is a good illustration (pun intended) of the point I'm trying to make. One complete segment of the country still doesn't realize this is the truth because so many out there don't want them to know who really ran up the deficit.
So we'll just have to keep hammering the truth back at them until MAYBE some day we get back to a country that's more open to truth and fairness, instead of being interested in their side winning no matter the cost.