So let’s be clear here, he was charged with felony murder of his accomplice in a dangerous felony. Felony murder is the crime of killing of a person in the commission of a dangerous crime.

It’s pretty debatable if it makes sense to charge someone for felony murder if they were an accomplice, but that’s a different discussion than the framing of “charged for a murder committed by cops”. The cops didn’t murder this guy, it seems pretty clear that the cops acted in self defense here. So it’s not like they transferred the “blame” as it were from murderous cops to an innocent kid.

The reason felony murder exists is that even if there was no actual intent to kill, the risk of death during a dangerous crime is so high it becomes reckless. There’s a similar crime of depraved heart murder where the act that causes the death of someone is so dangerous that one could only do it if they had no concern of killing someone. You go into a felony knowing someone could get hurt or killed and do it anyway, so you are responsible for the consequences whether you “pulled the trigger” or not. A more common example would be if you and a buddy are robbing a bank and your buddy kills a teller or a cop, you get charged with felony murder.