Substitutes for Thought
Labels
Labels, serving as terminology, are a necessary tool for discourse. On the other hand, they are a dangerous tool for thinking.
Labels immediately stop thought.
Once we attach a label to someone, we stop perceiving that someone's nuances and start perceiving what further reinforces the label in our minds.
I don't mean that people do this intentionally or in a mean-spirited fashion. It's simply a cognitive bias called confirmation bias, and no one is immune to it.
Identity
More often than we'd like to admit, we decide on what we do by asking ourselves “what would someone like me do?”.
If we identify ourselves with some group or some set of beliefs, we are beholden to act in accordance with that group's expectations.
Going against one's self-identity is immediately painful, as anyone can attest. Therefore, those that shape the self-image and the ideal behavior of some substantial group of people wield immense power.
Authority
Finally, the most common shortcut of thought is deferring it to someone else who has supposedly already done the thinking.
Authority is often a necessary tool of coordination. Having someone acting as leader often helps the outcome for the whole group.
But leadership is not an inherent attribute; it is the group who allows the leader to assume a position of authority.
A leader must be held accountable to the group that is allowing it to hold that role. Leadership is servitude, it is not a bestowed reward and it is not a self-aggrandizing ego boost.