Clark That's right. The Fortress of Solitude would be designed with a fail-safe. When the device was put into the console, the Fortress first cross-referenced it with all data. Since there were archives of your past conversations with Jor-El there.. it concluded that the device wasn't needed.
And in that case, your father had designed it that the Fortress would sacrifice itself and all that knowledge in order to save you. Plus, it knew that Lex was once possessed by General Zod, so that also worked against him. Your father would be damned if a human like that was ever going to control you.