Rent control has been a pretty effective way of preserving the identities of communities in cities. It's not perfect, but it helps. Concepts similar to rent control can and should be applied to sites trying to preserve certain characteristics.
A big part of political-economic maturity (for me at least) realizing that just because the supply/demand lines from your Econ 101 class don't line up, doesn't mean that something is worthless. It could be that you're not measuring everything. Culture matters, preserving social mobility matters.
Just kinda irks me when someone comes in with the Econ 101 argument regarding a policy that's being implemented by people with advanced degrees in city planning. These people took Econ 101, and know more about the subject than you or I. They could still be wrong, of course, but it's not for a silly simplistic reason like that.
It might be different in places other than California though, like New York.
Most economists believe that a ceiling on rents reduces the quality and quantity of housing available.[41][42] This view is based on analysis of empirical evidence as well as the understanding generated by theoretical models.[42] Economists from differing sides of the political spectrum, such as Paul Krugman[43] and Thomas Sowell,[44] have criticized rent regulation as poor economics which, despite its good intentions, leads to the creation of less housing, raises prices, and increases urban blight.
Now that I think about it further, it seems obvious that rent control would be a tool that can be used by a municipality to control rents in either direction, depending on their goals.