Putting aside the question of who keeps a calander for decades.
It’s a proven fact Kavanaugh has a drinking problem. Then and most likely now because he displays symptoms of it.
Even though he wrote everything down on that calander? As much drinking as he did it’s very possible he forgot to scratch off things he didn’t actually do. Also? Since he makes the claim that is what he was doing on those particular days? It is now he’s responsiblity to prove it. And with proof. Not just “I say I did it” he must have credible witnesses.
See how it flows both ways?