We usually do not think of it in that way, but you raise some interesting and valid points.
And you support that idea by pointing out the truth that, in religion and politics, herd mentality often dominates. I've lived in 6 countries now, and one thing I've seen is how a certain idea can become a predominant meme in a culture / society.
However, the minute one moves OUT of that society, it becomes clear that the idea is not the absolute truth, just an idea that took hold and grew and captured the mind-set of the people. But for various reasons, the people cling to it as truth, even past the point where the idea begins to have an insidious effect on the society.
It's difficult to overcome such powerful "thought control," but it can be done.
Think for yourself, and realize your own truth.