Why do protesters chant, "This is what democracy looks like"?

Julian Sanchez has an evolution-based theory:

For most of human history, we’ve spent our whole lives in social clusters of a few hundred people—we’re basically hardwired for groups of that size. That makes it easy to look at a throng of a few thousand out at a rally and tell yourself . . . : “This is what democracy looks like.”

Except, of course, it isn’t really. Or at any rate, it’s only a tiny part of what democracy looks like.

A small group of people self-selected for their commitment to some set of shared goals and values may be able to pick a set of slogans to chant in unison, or resolve their limited disagreements by consensus process. But real democracy in a pluralist society involves deep and often ineradicable disagreement—and not just on the optimal uses of public parks and other commons. It’s true, of course, that concentrated and wealthy interests routinely capture the apparatus of government, and use it to serve ends inimical to the general good. But a frame that sets up an opposition between “the 99%” and “the 1%” —or, if you prefer, between “Washington/media elites” and “Real America”—suggests a vain hope that profound political differences are, at least in some spheres, an illusion manufactured by some small minority. . . .

To imagine protest not as prologue to politics, but as a substitute for it, suggests a denial of the reality of pluralism, and an unwillingness to find out what democracy actually looks like.