Homeowners and renters are affected by these policies differently, often in opposite ways. That's the point. Obviously these NIMBYs are homeowners because their position grossly favors existing homeowners. Mortgage payments are not affected by a constant influx of new people but rent prices are. Stalling is a win for one side only. Anybody can wish for "preserving quality of life." But while they are wishing homeowners are reaping all of the benefits and renters are getting screwed.
I would be very surprised if there were more homeowners than renters in cities, and if there were---then what we have is democracy at work.
Consequently, I believe that many renters simply aren't participating in the political process or are strangely voting against their obvious interests.
The YIMBY platform will work because the majority of people will benefit from it, but need organization to actually get to the polling booths and participate in lobbying.