Consider how many years they spent pouring garbage in your head. You're not going to get it all cleaned out in a day or a month or a year. Everyone recovers at a different rate. It usually takes at least several years.
These clowns have carefully planted tendrils of their nonsense into every nook and cranny of your thought. Even if you rip most of it out by the roots, you will still be surprised, at least occasionally, to find one you missed. But eventually you can clean it all out, and replace it all with a solid grounding in reality.