"Christianism" Explained

A reader writes:

Use of the word "Christianist," and not being sure of its meaning, led me to Google the word. Among several links that popped up was a very helpful one from the Christian Science Monitor. For a while I've wondered why you used "Christianist" when "Christian" would be so much easier to use. Reading how "Christianist" came into use, and of its true definition, helps me realize what a damning word it is, and how very different it is from "Christian."

Yes. I mean by it the complete conflation of Christian faith and secular politics of the hard right. I don't see why I should concede my faith or my politics to those who share neither.