My point is, that he has admitted to speaking to the David Duke group when he did not actually do so. He probably doesn’t know who half the groups he is speaking to are. And if you speak to hundreds of groups a year, your chances of correctly remembering any particular one are low.
It was a dozen years ago. He apologized if one of the hundreds of groups he spoke to was a Duke sponsored event. It turns out it never happened but he thought he might have accidentally attended that event.