I think the decision was that off-duty cops have a reason to possess assault weapons, but retired cops do not. The reasoning is based on their assertion that such weapons may only be possessed for the purpose of law enforcement business. Off-duty cops might find themselves suddenly on-duty, but retired cops are just poor Kalifornia schmucks who don't need no stinking constitutional rights.
I think the decision was that off-duty cops have a reason to possess assault weapons, but retired cops do not.As I re-read it, it seems they found a "cops exception" to the premise that citizens have no costitutional right to have guns. AW seems to have nothing to do with it. I haven't read the decision yet.
Either way, lame law. Cops are civilians. (I know, they think think they aren't) This decision moves us closer to the unthinkable.