I didn't think we reached the point where people are arguing that things that make housing more valuable disincentivize building more homes - but here we are.
It is zoning restrictions, EIR, etc., that disincentivize housing.
Prop 13 absolutely disincentivizes building housing. Other policies can also be bad. But grandma's house isn't being bulldozed to make way for a quadplex because she's insulated from the market.
Stop calling people evil just because your grandmother isn't the center of their policy concerns.