Most people were never trained to think for themselves. They were sometimes punished for it when they were small and their actions did not fit into the prevailing culture. They were rewarded for conforming to the norm. This is a fertile field for anyone who knows the fears of the human mind with it’s desire to blame scapegoats. It is a perfect medium to dominate, control, and plant their ideas into.
As to not being able to control our own minds: It is possible to control this automatic and repetitive commentator in our heads. Most people don’t know this because they just let themselves be swept away by it. The first step is recognizing how the ego-mind works. It has certain patterns and they are not unique. That is what mind-controllers count on. After that, there are a number of proven techniques, such as meditation and yoga that can help with the rest.