While it can be frustrating that people can't take 1+1 and get 2, the psychology of it is that people are generally irrational. The wierdest thing is that when you get into an adversarial argument with people, they are more likely to reinforce their original belief than to ponder on new evidence. There are better ways to present information to people than the way you described. All that happens when you do that is they think you're a dick and ignore anything you present in the future unless they see you as an authority figure.
Aim to describe, educate, and communicate. Talk about the idea rather than focusing on the correction and you'll reach more people than if you take the current approach. Maybe you don't want to reach more people, but think about why you don't want to reach more people. Isn't that just a rationalization, justifying your way of thinking and way of life without wanting to learn the circumstances or mental capacity of those around you, limiting their ability to understand as easily as you? Its rationalizing the irrational negative feelings for others, the same exact behavior you despise of others.
I think a lot of it comes from the motivation for communicating. I approached it how you did when I was younger, but fortunately landed with a good company that taught me a lot about myself and let my strengths as well as limitations show through so I could see where to improve (communication). When I was younger, I communicated to find like minded individuals and to reaffirm my way of thinking and beleifs. Now, I communicate to share, learn, and educate.