Upon closer observation, it becomes apparent that every strong upsurge of power in the public sphere, be it of a political or a religious nature, infects a large part of humankind with stupidity. …
The power of the one needs the stupidity of the other. The process at work here is not that particular human capacities, for instance, the intellect, suddenly atrophy or fail. Instead, it seems that under the overwhelming impact of rising power, humans are deprived of their inner independence and, more or less consciously, give up establishing an autonomous position toward the emerging circumstances.
The fact that the stupid person is often stubborn must not blind us to the fact that he is not independent. In conversation with him, one virtually feels that one is dealing not at all with him as a person, but with slogans, catchwords, and the like that have taken possession of him. He is under a spell, blinded, misused, and abused in his very being.
Having thus become a mindless tool, the stupid person will also be capable of any evil and at the same time incapable of seeing that it is evil. This is where the danger of diabolical misuse lurks, for it is this that can once and for all destroy human beings.
Dietrich Bonhoeffer (1906 - 1945), “On Stupidity,” Letters and Papers from Prison.
Manipulating the stupid and taking advantage of that ignorance is quite sinister. It's mind manipulation when one does take advantage of another's ignorance. It's sinister because you end up using the other for your own gains and profiting only yourself. It's not sinister to help the other understand and bring them out of that ignorance to where they understand and can therefore gain and profit for themselves and everyone else that would benefit because of that understanding.