The Legislature finds and declares that in order to preserve a healthy housing market and avoid a two-tier market where publicly subsidized mortgage capital supplants mortgage capital supplied by private financial institutions, it is necessary for the lending programs of cities and counties to be sufficiently targeted to avoid competition with private sector mortgage lenders, and further that revenue bond financing of mortgage lending by cities and counties be reasonably constrained to avoid disruption of bond markets and the credit standing of the state and its political subdivisions.