I'll just speak for myself in answering your question. Other people who self-identify as rationalists may have other reasons. I self-identify as a rationalist because, after a lifetime of being curious and wanting to know what is true, I have found rationalism a powerful instrumental means of discovering truth. I have found from observation of my own life that knowledge of truth is itself an instrumental means for pursuing other useful goals (for example, making a living for my family) but anyway I think truth-seeking is part of human nature at its best and something fun and worthy for its own sake.
most bad things are propagated by extremely rational actors out of greed and self-interest
I might disagree with you about there being very many "extremely rational actors" in the world,
but I agree with you that many bad acts are prompted by greed and self interest. One of the greatest achievements of rational thought has been a deeper understanding of how human moral sentiments
and promises to provide continued blessings of more peace, prosperity, and freedom as it becomes more widely known to humankind. So I pursue rationalism as a positive good for my family and for my society, after having had a childhood upbringing with more nonrational dogmas than I know adhere to.
I'll just speak for myself in answering your question. Other people who self-identify as rationalists may have other reasons. I self-identify as a rationalist because, after a lifetime of being curious and wanting to know what is true, I have found rationalism a powerful instrumental means of discovering truth. I have found from observation of my own life that knowledge of truth is itself an instrumental means for pursuing other useful goals (for example, making a living for my family) but anyway I think truth-seeking is part of human nature at its best and something fun and worthy for its own sake.
most bad things are propagated by extremely rational actors out of greed and self-interest
I might disagree with you about there being very many "extremely rational actors" in the world,
http://www.project-syndicate.org/commentary/stanovich1/Engli...
but I agree with you that many bad acts are prompted by greed and self interest. One of the greatest achievements of rational thought has been a deeper understanding of how human moral sentiments
http://www.amazon.com/Theory-Moral-Sentiments-Great-Philosop...
can be motivated by the actions of human beings pursuing their self-interest.
http://www.amazon.com/Wealth-Nations-Bantam-Classics/dp/0553...
This discovery has resulted in considerable reduction of violence and other bad things over time,
http://www.amazon.com/Better-Angels-Our-Nature-Violence/dp/0...
and promises to provide continued blessings of more peace, prosperity, and freedom as it becomes more widely known to humankind. So I pursue rationalism as a positive good for my family and for my society, after having had a childhood upbringing with more nonrational dogmas than I know adhere to.