I frankly do not remember the Rodney King verdict, but it would fit. The article didn’t mention CA as having the same law against reduced charges by juries.
My first reaction to law about juries reducing the charges was that it gives juries way too much authority, beyond their capabilities. Usually, they say that if you get into a case where you are wrongly accused of a crime that you should waive your right to a jury trial for this reason, but in this case, the judge is not impartial. It is not a good position to be in.
Suggest you look into the concept of jury nullification. Juries have a lot of power.
IMHO, a jury should be allowed to come back with an verdict and sentencing range which is not one of the specific ones offered, but if either the prosecutor or defense objects, the jury should be informed of which party (or both) objected to the verdict and instructed to deliberate further. If the jury finds that the defendant is guilty, but specifies a maximum sentence that it would deem reasonable and such a proposed verdict is accepted, the judge should be forbidden from imposing any sentence beyond that. If the prosecutor objects to such a verdict, the jury would be instructed to decide whether it would rather issue a guilty verdict without such a sentencing restriction, or if--forced to make such a choice--it would rather acquit the defendant outright.
While it is true that judges are in many cases better qualified to decide sentences in a fair and consistent fashion, if the members of a jury would find that any sentence beyond a certain level would constitute cruel and unusual punishment for the particular acts of the defendant in the case before them, then no sentence beyond that level could be legitimate under the Constitution.