It's not tolerance. It's surrender.

Popular morality works through a zero-sum game. In its view, if we remove all of the bad, we are left with good. Under the Platonic conception, we have a duty not only to avoid bad, but to actively achieve good, even through bad methods. This means that pacifism, withdrawal and tolerance are not moral goods, but moral ills.

In this difference the extremity of conservatism emerges. It is not enough to avoid acting in a way that appears scary. Nor can one hide behind approving of everyone and everything. In contrast, we each have a duty to do what is moral in order to conserve the ongoing direction toward what is good. While this makes us all policemen for social order, it also obliterates the complacency that allows civilizations to slide toward chaos.^[1]

Complacency ensures that our borders remain open. Why? Because leftist think that all discrimination is bad and discrimination against foreigners is especially bad. Stopping foreigners from entering the U.S. and denying that every foreigner in the world has a right to come to the U.S. and vote are discriminatory. Ergo, not enforcing our borders -- and devaluing U.S. citizenship -- are good.

Result: we are left with the left's precious, beloved, moronic "diversity," the perfect formula for importation of and tolerance of our enemies, ethnic strife, and bloodshed.

Notes
^[1] "Conservatives, turn to Plato." By Bret Stevens, Amerika, 12/2/15.