Citizen Kane: Who is Rosebud?

In Robert L. Carringer’s article “Rosebud, Dead or Alive: Narrative and Symbolic Structure in Citizen Kane,” he indicates that “Rosebud becomes the symbol of [Kane’s] youthful innocence, lost when he was adopted into a family of bankers.”
Adversely, he believes this to be a “fallacy” and I completely disagree with him. His reasoning on disproving this apparent fact is weak and ill-conceived. He is very critical of the film throughout the article and at times calls the best film ever made it “gimmicky.” He writes through his argument, quoting things that he’d never be able to write, and at times passes up the simple explanation for the elements of the movie. Citizen Kane is really that simple: Rosebud is his childhood.