Progressives are not objecting solely on the basis of “character of the city” and in fact regularly poll in favor of development. What they fight for is affordable housing development.
Underlying this problem is a massive income disparity between techies and working class folks. Essentially the YIMBY position is if you build market rate housing for techies it will trickle down to the working class because “supply and demand didn’tyoutakeeconomics???” But Econ 101 has within it the concept of inelasticity that explains why increasing supply does not always move the price much under certain conditions. Like those of say a massive boom economy where tons of high income earners and speculators from around the world are waiting to snatch up new inventory. SF has had many experiences with such boom/bust cycles.
It’s a real estate developer’s dream and it helps us rich-ish techies (hence heavy YIMBY presence on HN) but it doesn’t necessarily translate into lowering rents for the working class. Thus, progressive supervisors are focused on public investment in affordable housing and taxing the rich to fund it, not just serving the needs of the wealthy.
YIMBYs absolutely hate this characterization because they like to claim they are on the side of the poor. But they are 100% aligned with and politically funded by the real estate industry, and that’s why they prefer to mischaracterize progressives who are actually prioritizing the needs of the most vulnerable.