I have never met a left wing person who is pro landlord, is this some weird American spin on "the left"?
It's a variant of a straw man that right wing people sometimes use. Which makes sense given that OP is forming their perceptions of the left from a book subtitled "How Progressives Destroy Cities".
(Conservative areas are generally both socially, and economically conservative. I know someone will mention Utah's housing first program, and I'll cut them off at the pass, by pointing out that subsequent governments have been severely under investing in it.)