The shibboleth was a test of who was on whose side; and that, according to the evolutionary psychologists Leda Cosmides, John Tooby and Ray Kurzban, is what group markers are really all about. Signs of affiliation help to turn a melee of floating faces and animated bodies into meaningful patterns. They let individuals understand who is with whom and what is going on. Humans are not simply social beings but political ones. From playgrounds to corridors of power, they are constantly forming, modifying, ending and generally complicating alliances. Stable cues that signal alliance, such as speech traits or styles of dress, offer regularities that help people orient themselves in the social whirl.
Like many issues, regardless of what “side” you support, a failure to recognise that your opponents are not monsters, are indeed striving moral beings like yourself, is an unhelpful, immoral attitude to hold when engaging in discussion. What occurs from this lack of humanity, aside from unnecessary character attacks, stereotyping, ad hominems, and Strawmanning, is an inaccurate assessment of your opponent’s view: being inaccurate means being wrong. This is primarily why I defend, so strongly, a principle a charity.
I want to be right, just as I assume we all do. To mount an argument that, in fact, does nothing or little to counter what your opponent actually says would be exactly doing it wrong. Thus, to be charitable has nothing to do with being “nice” but being accurate. I care more about my arguments being accurate than whether I come off as a guy you want to have a beer with: hence, my attempts at charitable reading are focused on accuracy, not friendliness.
Demonising, character attacking, mockery and so on are indicators of knee-jerk responses that provides no insight into the debate itself - only into your personal reactions, which, save your diary or loved ones, are of no concern to us.
Tauriq is correct in that, if you care about truth above all else, you should be impatient with distractions from pursuing it and extremely wary of the cognitive and emotional biases that will prevent you from perceiving it. But the problem is, most people are willing to ignore, distort, or otherwise subordinate truth to their psychological needs (and they're not necessarily wrong to do so). Thinking hard and researching take a lot of time and effort, and honestly, a lot of mistaken or ignorant opinions "work" in the context of everyday life. That is, people can be anywhere from slightly to completely mistaken on a wide range of issues without it dramatically affecting their lives in a negative way. Even the most reactionary fundamentalists can live a life in which their most basic needs are met; they can enjoy luxuries, know love, and reinforce their identities within a community of like-minded people. Seeking truth, however much some of us may value it, is only one of many supplementary "purposes" humans have come up with to justify their existence.
In any context involving an audience, especially in the fishbowl environment of social media — where, if a person expresses an opinion and it isn't liked, plussed or rewteeted, can it even be said to exist? — posturing for attention and approval is going to count for just as much, if not much more, than suspending judgment and being careful about facts. Sam Harris makes a controversial, counterintuitive claim about gun control. As is usually the case, people react to the presence of a discomfiting idea the same way they would to signs of contagious disease in their neighbors, by panicking and seeking to quarantine him. In this context, Ian Murphy's aggressive bluster is a way of reassuring everyone that this intruding idea is so ludicrous as to not be worth considering for a second, while not so coincidentally gaining status for himself as the guy who told us what we desperately wanted to hear. The emotionally-charged invective serves as psychological cement to fill in any logical cracks that appeared in our worldview. We don't need to think about it as long as we make ourselves feel better for now.
I overcome this urge in myself by reminding myself of my own powerlessness and insignificance. I don't mean that in a twisted, debasing way. I just mean that I stop, take a deep breath and acknowledge that I am merely one antisocial individual with no power, wealth, ambition, prestige or influence, and I have nothing better to do with my time than attempt to understand things as fully as possible. My opinion doesn't count for anything, so I don't need to feel pressured to add it to the chorus, and the possibility of revising it doesn't feel like a threat of having a limb amputated.