Immigrants are required to possess a modicum of knowledge about the Constitution, the Declaration of Independence, and the system of government, not to mention some level of command of the English language (my wife teaches citizenship courses to immigrants). I, myself, am a naturalized citizen, from Canada, and I had to swear an oath to uphold the Constitution, forbear allegiance to foreign powers etc.
It's a ritual, but rituals have meaning and power. It would be nice to see more native-born Americans with a strong grounding in democracy and electoral politics.
When we had a mandatory military draft, at that time most able bodied young men were required to put on a uniform, salute the U.S. flag, march to patriotic music, etc.
Today this sounds trite and even anti-democracy -- weren't we indoctrinating generations of gullible young people to just blindly follow the leader?
Yet, today, many young people including college graduates are hardly patriotic at all, and are mind-numbingly ignorant of even the most basic facts, as illustrated by man-in-the-street interviews posted on Youtube by wags like Ami Horowitz and Mark Dice, getting college students to admit that the triceratops (an extinct dinosaur) is endangered and trophy hunting of this poor beast should be banned, and similar ridiculous notions.
Even during the Vietnam War, one survey in about 1970 found that 25% of Americans thought Vietnam was in South America.
Education is the key, and by that I believe you and I both agree that indoctrination in particular directions is not the same thing. My kid in high school... well, I could tell you stories, but I'd better stop :)