If you are instructing children that anyone who looks or talks or thinks differently or has different customs than than you do is wrong, inferior, less than human, not to be tolerated—-that’s indoctrination. The problem is not with the doctrine itself, but presenting it as the exclusive truth, beyond question, and making it the sole criterion for whether you treat others well or badly.
Values, principles, require thinking because they are often multi-faceted, different values may come into conflict in a given situation, and values require learning by experience, modeling by example. No amount of repetition of songs and chants and stories will instill a value. You can’t memorize it. A child may learn to recite a moral proverb but unless he/she/they have seen or experienced that value in action, in a variety of situations, the child’s behavior will not be influenced.
Obviously indoctrination works, at least to suppress dissent in most people—Orwell had witnessed that with the Nazis. But it destroys relationships, and even when it creates outward conformity, it can’t suppress all independent thinking. People are not robots.