They aren't smart enough to figure this out on it's own.
Many of the rest of us put the pieces together rather quickly way back during COVID.
Now that his actions are being more clearly exposed and simplified (he fucked over everyone else - even children - in order to preserve his reputation and career, for the celebrity and adulation that he coveted, and to stay out of jail), they understand it, but they still initially refused to believe it because their media sources spin it.
Now that it cannot even be spun (Fauci just pleaded the 5th 111 times despite having a full pardon back to 2014 while his top aid just pleaded guilty to covering the evidence), their media messagers just appeals to their obsession: "Whatabout Trump!"
They are not a bright lot.