Please see the firt part of the reply to Alamo-Girl. Hitler organized Nazi youths into the Hitler Youth Corps. Whether its history or mytholgy, they paraded and parroted goose-stepping storm troopers. Some reportedly served as informants to identify Jews and other "enemies of the state". Lenin and Mao formed similar youth organization. These are nothing more than propaganda and indoctrination methods for budding socialists, where people are trained to react based on emotions tied to patriotism in a warped sort of way (my country is my country, right or wrong). The idea is to short circuit the thought process. If people thought through what they were being asked to do, many would have resisted or even rejected it completely.
No one would disparage allegiance to a country that is doing "right" and living within the Constitution.
This country has not lived entirely "within the Constitution" since the moment it was born. And, in spite of the best efforts of many, instances of injustice have, are and probably always will occur. You're either with us or against us.
A pledge of allegiance is not about knee-jerk patriotism it's about loyalty.