Xavier is always up to some shady things, but I honestly don't think that he, or any of the other telepaths involved in that process, actually are privy to every single thought in a person's mind when they do that Cerebro transfer. To me it feels like they just move the folder from one spot to another, not that they go through every single file, if you get what I'm saying. Even when they do the Cerebro copies. It's more like taking a photo by just pressing a button and letting the machine do it's thing, not mentally scanning and recreating everything by hand, pixel by pixel, so to speak.