Maybe there's the possibility the prosecutors, since this is San Francisco, overcharged on purpose. Who knows when you're dealing with these people.
No overcharging in this case occurred. The prosecution simply failed to dumb it down enough for an illegal in san Francisco. If you are a white guy wearing a MAGA hat and you did this, you would be looking at life in the slammer.
The prosecutor followed the law and his duty to bring appropriate charges, including alternative charges where the jury could find guilty for lesser crimes. At a certain point he just could not take the San Francisco out of the case. I don't know how prosecutors get in office there- whether appointed or elected- but if you are a prosecutor in a state where you are elected and you did not protect the people by bringing murder charges then you are not going to be re-elected- not because it is politics but because you are not performing your oath of office.