Don't you see how you feeling offended by it is exactly the point that is being made in the article, that it creates pain, because your belief system makes you think it is wrong, and not only "a different equally valid opinion"?
The core idea here is to not merely "tolerate the pain of difference", but "dissolve the pain" by realizing how the only thing that causes the pain in the first place is the belief that one belief is wrong and the other is right.
Q.E.D.?