Aside from all the hypocrisy etc... isn't this concept just plain wrong? Doesn't more housing + business increase the property value of an area? I could see the first-order effects being a reduction of surrounding property as supply increases, but the second order effects of more people are almost always accretive. The downtown area of a city is typically some of the most expensive real estate.
Atherton is literally a town of nothing but mega-mansions with very, very little in the way of commerce or industry. Its entire raison d'être is to be a retreat for the ultra-wealthy. Having ordinary people walk around in your billionaire enclave lowers property values.
I understand this is the argument is being made. This just seems to me like this is an opinion stated as if it were a fact, and not a tautological truth of property valuation.