From the transcript of the Darkstream:
If you look at at other mistakes that people make I would say probably the biggest one, and the one that is the biggest single problem, is the tendency to apply the genetic fallacy. You see that applied all the time to people like me who are on the Right, but you also see people on the Right applying it to people on the Left. What you need to understand is that it is a logical fallacy to dismiss someone because of the nature of the source. Let me rephrase that: it is a logical fallacy to dismiss something based on the nature of the source.
So the fact that Sam Harris is saying something does not mean that it’s going to be false. Now, if he is playing around with words and that sort of thing then you can have a heuristic that says: Sam Harris is babbling about definitions again and so he’s probably wrong, he’s probably not telling the truth. So it it’s a useful heuristic, but again you cannot place any heavy reliance upon it. You always need to check and you always need to pay attention. What’s what’s important is you apply the heuristic when you don’t have time, but at no point do you ever claim that it has proved anything.