You know if you wanted to brainwash people you could really do it as well (not that I am giving you the idea to), because you have the power and the resources at the disposal to do so.

Another thing why people are easily brainwashed is that majority don't care or have the time to properly investigate what the brainwasher is trying to do. They don't make the effort to see if there is truth about the type of propaganda that is being spewed because no one wants to make that effort and influential people understand this and take advantage of it.