with the OP's question:

from Carl
How come this country of ours that professes to be a cut above, the city on the hill, is probably going to abandon millions of people to lethal killers again?
In answer, it will continue to do so until (1) it ceases to preach that it is "the city on the hill"; and (2) it ceases to preach that it will safeguard "millions of people" from "lethal killers".

It will continue to do so so long as its strategy continues to be based on what was so clearly stated to be US strategy in Afghanistan from the gitgo:

Future of Afghanistan
Richard N. Haass, Director, Office of the Policy Planning Staff, and U.S. Coordinator for the Future of Afghanistan,
Testimony Before the Senate Committee on Foreign Relations
Washington, DC
December 6, 2001

Mr. Chairman:

I am pleased to have this opportunity to testify before the Committee on Foreign Relations in my capacity as U.S. Coordinator for the Future of Afghanistan.

Our aims in Afghanistan are well known to the American people and this Committee. We seek to bring about an Afghanistan that is free of terrorists, that no longer is a source of poppy, and that allows its citizens -- including an estimated five million refugees and an unknown number of internally displaced persons -- to return to their homes and live normal lives in which opportunity comes to replace misery. ... (JMM: much more of the same in the rest of the statement).
Not to blame Mr Haass too much, who was simply following in the footsteps of a flock of US Presidents (from Wilson to GWB, at the time) and stating what his boss Colin Powell wanted stated.

If one believes that the US is "the city on the hill" and has an obligation to safeguard "millions of people" (actually "billions") from "lethal killers", then one is obliged, I suppose, to preach what Mr Haass said. The problem is that, if in the course of these neo-colonial wars, one must pull the plug, charges of hypocrisy are well founded indeed.

I do not believe that the US is "the city on the hill"; or that it has an obligation to safeguard "millions of people" (actually "billions") from "lethal killers" - other than its own citizens. I am therefore a "bad, evil person".

Regards

Mike