In psychoanalytic therapy you generally let the idealizing transference fizzle out on its own. One reason is you learn alot about yourself throught that process and get to know yourself, who you are.

Children idealize their parents at a certain age just the same, which has many more layers than that avoidance theory. But there's something called 'splitting' where you see people as 'all good' to protect yourself; children do that . The other end of that is sometimes devaluation. That is sort of a defense.