It is a reasonable statement to say that the witnesses refuted Ford when she says they were at the party, and they say that they don't remember it.
It is also reasonable for Kavanaugh to say that he was never at a party llike Ford described since she gave multiple specifics of the scene if, conveniently, nothing that could be used to
corroborate her story. He did not say he was not at other parties in his day, just not one like she described. I wouldn't think twice about describing it that way myself in his shoes without ever imagining that the Left would be looking to split hairs like they are now.