The writer of the story doesn't realize that the heroes were playing "holier than thou" as much as the Christian. You see, they were condemning the Christian for saying what she believed and threw the Christian out because of what they believed. They deemed their belief to be better than that of the Christian. They were thinking that their belief was holier than that of the Christian's.
This happens all the time. The people with the bumper stickers which say "COEXIST" think that anyone who makes an exclusive statement should be condemned. For example, I believe that we should love all people of all faiths and all lifestyles. I do not believe that everyone's value system or faith is just as true. In fact, I know that they are exclusive of each other. The ones with these bumper stickers are intolerant of me for saying that Muslims or Hindus need to come to know Christ. They have violated their own bumper stickers because they don't want to coexist with those who do not accept all beliefs. They think that their own "coexist-ism" trumps my belief. They are not actually coexisting like they think I should coexist.
Evidently each person tries to find a way to justify the way he or she is living. Each person looks for a group of people who will confirm that belief. Therefore, the value system will not allow those who challenge a contrary belief to stand unchallenged. For example, I think that slavery is abhorrent. Let's say that someone who espoused slavery as good moved next to me. I believe that it would be natural for me to condemn him. I would magnify every flaw I discovered in my natural self.
Now this is the key: As a believer I must be more than my natural self. I must not condemn others even when I don't believe as they believe. That does not mean that I don't know that they are condemned. It means that I am not the one to pronounce condemnation.
I do lots of funerals. Sometimes the local funeral homes call me to do funerals for people who have no church. Sometimes families give me no indication that the deceased have been saved. It is not my place to determine if the deceased are in heaven. I can't do anything for them anyway. So, I preach a gospel story for those who have come to the funeral. I tell how those who come to know Christ will never die. I never tell the families whether or not those who have passed away or in heaven or hell. I really don't know.
Jesus told us not to judge others. He did so just before He told us how we needed to get the log our of our own eyes before we got the speck out of the eyes of others. He wanted us to see our own sinfulness before we addressed the sinfulness of others. Those who have come to know Jesus should be the ones who know this better than anyone else. Those who know Him should never stand over those who sin with a triumphant smirk. How will we ever stand our own judgment if this has been our attitude toward others.
Christians should not be surprised that others do not act in this way. They want our conversions (just as we want theirs) or they want to stand over us triumphantly because they are right and we are wrong. Of course, they won't see it that way. They'll think that their system of belief is better than ours.
Doesn't that give them the right to judge us thus? (I hope you know the answer to this.)