This is interesting - I've known for decades that imagery (movies) are best avoided if one wants to keep a clear view of reality. The clue I followed was from those dreams that are so close to reality that when you wake up from them it's difficult to discern whether the dream event was true or just a dream. That served as a warning to me about the power of movies.
But what is not touched on in the exchange posted is the powerful effect of being anchored in God's reality revealed in Scripture. I always use Scripture as a plumbline - a standard against which to measure truth and lies, good and evil. When the Bible has been read as a whole, and many times over a lifetime, it becomes a foundational base for life and keeps one grounded. If I were a betting person I'd bet that the ones most difficult to hypnotise or brainwash are Bible-believing Christians although they are not mentioned in the analysis.