The goal is not to proof that they didn’t do it, or even to make it the rational assumption that they didn’t do it.

The goal is to muddy the water just enough, so some people can subscribe to “it’s complicated” (note how we hear that one a lot these days) or “innocent until proven guilty! And where is the convictions?!” By gaining the information advantage, they effectively demobilize actions towards prevention before or prosecution after. Also it gives just enough wiggle room, so allies can continue to support and opponents struggle to muster definite action.

This game is played expertly by the US, by Russia, by Israel, and China, and used to be played by the Nazis, Pinochet, UDSSR and many more.

It is crucial to collect evidence and it is crucial to never relent demanding investigation and prosecution. Otherwise we’ll get some historians in a hundred years writing a book about everything that happened and everybody will just be like “a well that was ages ago now, wasn’t it?”