In Shakespeare's play The Taming of the Shrew, a strong-willed woman named Katherina (Kate for short) is brainwashed (through the withholding of food and clothing, among other forms of psychological abuse) into becoming the ideal submissive wife. Her husband, Petruchio, tests her obedience by insisting that the sun is the moon and that a man is a woman. Having given up her free will and any desire to think for herself, Kate agrees with Petruchio's absurd assertions.
A frighteningly large segment of American voters have become modern Katherinas. No longer interested in checking facts for themselves or questioning their lords and masters, they willingly accept (contrary to Occam's Razor and all observable evidence) that President Obama was born in Kenya. They not only refuse to believe that human-released greenhouse gases have anything to do with climate change (which is not an outrageous position, since evidence of a strong correlation is not proof of causation), but that average global climates are even rising at all. They believe the expertise of a pampered English aristocrat with degrees in classics and journalism studies over that of actual climate scientists at NOAA or the Woods Hole Oceanographic Institution. Some of them continue to insist that homosexuality is simply a lifestyle choice or a condition that can be "cured" (despite a growing body of scientific evidence to the contrary, not to mention numerous sex scandals by conservative clergymen who have strong incentives to play it straight), and that it is therefore OK to discriminate against homosexuals.
Some right-wingers will undoubtedly claim that the left are the ones who are uncritically accepting a belief in global warming or the normality of homosexuality. They do not seem to realize (or care) that lefties are more likely to question everything. There are some on the left who form their opinions based on tribalism or a desire to rebel against their parents, but the left is not monolithic. There are all manner of free-thinkers and skeptics on the left, and for an idea to survive, it needs to fit the evidence. When new evidence is discovered, ideas and models to explain the world are adjusted and/or discarded as appropriate. That is part of the scientific method.
From time to time, I find myself in a discussion that feels like I'm being told that the sun is the moon. At that point, I usually despair of having a rational and productive debate. Once someone has submitted to Petruchio, trying to debate the issue is like banging one's head against a brick wall.