I noticed that (although nearby Carson is hit as hard, but is not ritzy in the least).
I think it's because all of those people are popping by Cedars Sinai or calling their personal physicians and getting tested. Somehow, the rich are always able to get tested for things. I know Cedars has quite a few test kits.
Either that or they were as social as they usually are and got it that way. All over SoCal, regular people are still having birthday parties and bounce houses have been sighted.
In Santa Barbara, people are being diagnosed with CoVid without a test (the old-fashioned way, by doctors who believe they have a clear idea of the cluster of symptoms) and not being given a test (therefore not appearing in the official stats). I think that's happening in my city, too. But apparently the wealthy are wanting to be tested (I don't want to waste a test if I don't have severe symptoms, frankly).