As I mentioned, statements against interest are indeed the types of things that people will use in court to show that something happened. The claim made is that Trump did something he said he did. If you choose to believe he was arbitrarily lying in that conversation despite it being against his own interests, then how would you be able to trust him enough to TRVST THE PLVN? Doesn't exactly seem like a reliable person.
This is, of course, setting aside that you do not need to meet a judiciary standard to dislike somebody, especially not on this website. I don't think the favorite conspiracies of the A&N race, be they loony or reasonable, are going to be proven in courts of law anytime soon. But does that actually matter when it comes to perception?