As time goes on, the better I appreciate the perspective of people like Thomas Sowell, who has mostly stayed out of the libertarian "scene" because he's not a joiner. For understandable reasons, he doesn't want to join a crowd of like-minded people. Instead, he prefers to use his mind to follow the facts and lead him to his own conclusions.
Of course, everyone says that this is what they do. Everyone says that they just analyze the facts and the data and make up their minds accordingly. The truth is, however, that most people filter their information through ideology. They embrace or privilege any fact that fits their preconceived notions and reject or penalize any fact that stands in opposition to what they want to be true. And, true enough, nobody's perfect.
Still, imperfection is one thing; actively fostering confirmation bias is something else entirely. Anyone who knows what confirmation bias is ought to be actively engaged in avoiding it. Sadly, many people know what it is, and work actively to promote it anyway.
For example: I recently saw a web-comic that claimed that all those who oppose allowing transsexual girls to compete with cisgendered girls in girls' competitive sports are really just bigoted against transsexuals. The exact claim was that you don't have to scratch very far beneath the surface to uncover anti-trans bias. I responded to this web-comic with some biological facts about how testosterone impacts athletic performance, and concluded my comment by saying that I didn't think everyone who is reluctant to allow such competition is automatically biased against transsexuals. The reply? "I never said that they were." No, the person to whom I addressed my comment did not - but the comic that we were all discussing sure did! How did that context get dropped?
Second example: In a discussion about how more people die from suicide by hand guns than are murdered by long guns, a friend of mine quoted someone who was arguing in favor of greater restrictions on hand guns. I emphasized a point in that quote, highlighting the fact that hand guns aren't seen to be as "spooky" as, say, AR-15s, and thus they don't get as much attention in gun control debates. Many people responded, essentially asking me what my point was. But that was my point. All of it. I didn't have a further agenda.
What these two examples highlight is a practice I've taken on recently, which I do increasingly more often. Rather than make a broad and all-encompassing argument in favor of X or Y, I like to find a simple point that every reasonable person can agree with, and highlight it. It has to be a factual point, and it has to be mostly unobjectionable. What I find is that highlighting this point also tends to highlight my interlocutors' own cognitive biases. They think I'm trying to "get them" (actual verbatim quote of one such person, by the way), when they've merely "gotten themselves."
To correct their opinions, they'll either have to come up with different reasoning for the same conclusion, or refine their reasoning to account for an undisputed fact that favors the other side. That's my agenda. Sticking to and emphasizing the bald facts and forcing people to consider them when they articulate their own points.
Their doing so will make us all better off.