Why is the word "democracy" not in the preamble of the US Constitution?

In other words, our Founding Fathers and other Whig intellects of that time well understood that democratic methods are the surefire means to do serious damage to the rights guaranteed under republican self-government.

To blacks: “You can’t drink from that water fountain… eat in this cafeteria… ride this bus… go to this school. We voted fair and square and your side lost.

To slaves: “You can forget your notions of freedom. We voted fair and square and your side lost.”

Which album is your favorite that's now 50 years old (from 1975), and what's the best song on the album?

Majority-rules democracy is the way that majorities run roughshod over minorities, destroying rights and all ideas of equality under the law. No fair-minded person wants anything to do with democracy.

—Thomas Jefferson

—Alexis de Tocqueville

Eius sequi culpa animi quod delectus deleniti deserunt.

[with republicanism being the rights-protecting form of governance afforded us by our Constitution]

The republican is the only form of government which is not eternally at open or secret war with the rights of mankind.

To Indians: “Pack up what belongings you can carry and start walking to Oklahoma. Your fertile lands are ours now. We voted fair and square and your side lost.”

Most people obey arbitrary rules even when it's not in their interest to do so, experiments show - Phys.org

—John Adams

Another tendency, which is extremely natural to democratic nations and extremely dangerous, is that which leads them to despise and undervalue the rights of private persons.

When the people find they can vote themselves money, that will herald the end of the republic.

Could You Live Without a Computer? I Can. - The Free Press

Why? Try these on for size:

—Benjamin Franklin

Meanwhile, when the Democratic Party formed in 1828, it was with a Tory outlook keen on robbing others of their rights:

DL Coach Kris Kocurek Explains why 49ers Traded for Bryce Huff - Sports Illustrated

I do not say that democracy has been more pernicious on the whole, and in the long run, than monarchy or aristocracy. Democracy has never been and never can be so durable as aristocracy or monarchy; but while it lasts, it is more bloody than either.