But you just said “And that evidence must prove beyond a reasonable doubt not just that Caylee died, not just that her death was a result of an action of another, but that Casey herself was directly responsible for Caylee’s death.”
In the absence of direct evidence, how can you ever be sure?
How about time of death establishing that Casey was the only one of the family who would have been near her daughter? How about cause of death pointing to cholorform poisoning?
Either of those two facts established probably would have tipped the scales.
The prosecution has a tough job. And it’s supposed to be tough, the system is designed to let some guilty people walk to ensure that innocent people aren’t falsely convicted.
It’s not a perfect system, no system is, and yes, people “get away with murder”, plain and simple. But the alternatives... we fought a war to get away from the alternatives.