In this particular case, Naomi, I think you're clearly misunderstanding my point. Perhaps the below will make it plainer.
It's now established as a matter of fact that there were multiple parties in Downing Street, at a time when there weren't supposed to be such events according to the rules of the time. The question of whether or not they broke the law to a criminal standard we can set aside. Also, let us accept as a starting point that Johnson himself was unaware of these goings-on, or at least of most of them. In those circumstances, Johnson himself has been lied to or misled by his officials, and he has been embarrassed by them nationally for weeks on end, dragging into months. He should be furious. The line about having nearly died himself fits this narrative perfectly.
Where, then, was it? At the moment it seems to me that Johnson's anger, at least in public, is not at those who caused the issue, which I assumed above does not include him, and instead at those who continue to bring it up.
It is, at the very least, a serious missed opportunity in this case. "There is a culture at Downing Street of contempt for the rules and contempt for those whom the officials are supposed to serve. I have failed to stop it thus far. I will not continue to fail one moment longer" strikes me as a very powerful message. Coupled with that personal story, of how the contempt is personally wounding because it attacks victims of the very disease of which he himself almost died, I would have thought that ironically there's some political capital that Johnson could make of this.
In essence, this is what I'm criticising Johnson of the most: he's just suddenly bad at politics. It barely matters if he was at any of these events or not. It *does* matter that he hasn't shown any capability in dealing with the matter remotely effectively.