Experience has taught us that people will often employ outrage and hyperbole, often in the form of public shaming, to convince others rather than construct a sound argument. There may be several reasons for this. The research suggests that people generally find it easier to remain in the brain's equivalent of autopilot (system 1) than to employ slow, deliberate, analytical reasoning (system 2). [See Kahneman, "Fast and slow Thinking"] It seems that system 1 is the default. It may simply be that many find it easier to appeal to emotion than to do the mental calculus required to appeal to logical validity. Moreover, appealing to emotion persuades audiences more often than logic for the same reason.
Most of us notice early in our careers as Homo sapiens that by appealing to pathos and ethos, we can gain an immediate and substantial payoff in return for little effort. Valid logical reasoning, fact-checking, and careful introspection seem to come less naturally to us. And so, whether consciously or subconsciously, we learn the subtle art of persuasion. We learn how to appeal to the gut rather than the brain. Public shaming is perhaps the best example.
Public shaming is often used to silence dissent, to grant one's argument immunity from public criticism and deprive others of the opportunity to have their voices heard. In such cases, the desired effect is to use outrage to bypass the cognitive faculties of an impressionable audience. It is a way of assuming what one should be trying to prove in such a way that people don't even notice that one has left out the argument. But beyond the attraction of being able to manipulate the emotions of one's audience, there may be an additional motivation for public shaming, one that people sometimes overlook, and that is outrage addiction.
If you look around on social media sites, you'll likely soon discover several examples of outrage junkies, people who are regularly outraged over one issue or another and seem to be drawn to any chance to claim outrage. There are probably several motivating factors for outrage junkies, the most compelling probably being that it is cathartic. Outrage junkies get their fix from a heady mix of schadenfreude and the immediate sense of power they obtain by claiming moral superiority. This includes the feeling that one can be rude without the normal restraint of social etiquette once one has labeled another as morally inferior to oneself. This is where the real catharsis begins.
In the Middle Ages people would often gather with a sense of glee to witness, and in some cases participate in, the inflicting of torture and slow death on a person as soon as she had been labeled a heretic or witch. In many cases, ethical restraint and compassion went straight out the window.
It is not unreasonable to assume that modern people have many of the same motivations and cognitive biases as their medieval predecessors. The only course of treatment so far (assuming one is unhappy with this state of affairs) seems to be education, the rigorous exercise of critical thinking, and introspection. Physicist and Nobel laureate Richard Feynman once said, "The first principle is that you must not fool yourself -- and you are the easiest person to fool."