The author's larger point about the situation in SF seems reasonable enough (I don't live there, so I'm taking his word for it - obviously I'd change my mind if

The author's larger point about the situation in SF seems reasonable enough (I don't live there, so I'm taking his word for it - obviously I'd change my mind if his facts turn out to be false), but I don't buy this logic of "this guy killed someone, and if we had incarcerated him then we wouldn't have, so therefore we obviously should have incarcerated him earlier." By that logic, you should just keep everyone who has ever committed a crime in jail, because some portion of the people who you release will eventually do something awful. That road leads to madness.