NTS is not an actual fallacy per se, but rather an illustration of other fallacious thinking, such as "moving the goalposts". Simply stated, the claim is made about someone's actions or character. When an exception is found, it is waved off because the person is not genuinely part of the group:
- No Scotsman puts sugar in his porridge.
- But Angus MacDonald puts sugar in his porridge!
- Aye, but no true Scotsman puts sugar in his porridge.
But if you point out the NTS fallacy when atheists are guilty, watch out! I had an interesting encounter that illustrates this. Selected comments:
- I said, " Westboro strikes me as a non-Christian cult. I would not associate with those people."
- An angry atheist said, "Westboro Baptist Church, biblical literalists, are not Christians...I've heard it all now. Talk about no true Scotsman. No Christian is dropped faster than those that bring bad press."
- A friend added, "OK, you want to lump Westboro in with Christians? When Christians who know their Bible, say that Westboro is not acting in accordance to the Bible? We have been through this! You do not like it AT ALL when we call Stalin a true atheist. You do all kinds of gymnastics to distance yourself from the atrocities of atheist regimes, but you do not hesitate to throw in false religion in with true Christianity. What a double standard."
- Angry atheist number two said, "Say Stalin was an atheist all you like. It's when you start saying he did what he did BECAUSE of his atheism you start being wrong."
- Angry atheist number three chimed in, "Stalin didn't hold up a book about atheism while he was yelling at gay people."
That last comment ("Stalin didn't hold up a book about atheism while he was yelling at gay people") was amazingly absurd, equivocating the murderous rampages of atheist tyrants with Christianity. Also, it was a Straw Man argument.
Edit: Author S.E. Cupp is considered a bad atheist (or not a "true atheist") because she is not vicious; it's the opposite direction for the fallacy. Click here for a shining example of the "No True Atheist" fallacy.
The lessons here are to (obviously) be careful of someone making excuses so that they can insist on their arbitrary pronouncement. The second is to make certain that we are not guilty of making the same error ourselves. And Christians do not need to be intimidated by unwarranted accusations.