Second, while I'm the first to acknowledge that SF needs to build up, it's clearly absurd to say that the tech boom is "not the cause" of the city's housing problems -- that's like saying that skiing isn't the cause of Aspen's housing prices. Nonsense. It's plain that tech is the proximal cause, even if you believe that the boom has brought both positive and negative consequences to the city (as I do).
Fair debate on this topic has to begin with the acknowledgement that the tech companies' policies are indirectly driving a displacement of non-tech workers from the city. It's dishonest to claim otherwise.
[1] http://www.bayareacouncil.org/about-us/member-companies/