Most proponents of low-income housing I know of would like to vastly increase density and lower the number of SFH but the vast portion of the market and voters does not want that at all since it would lower their home value.
Increasing density generally increases existing home values more than not doing that; the land becomes more valuable (for free!) if more houses can be sold on top of it, and that's almost always worth more than having renters nearby.
The more common reason people vote against it is because they want their neighborhood to be frozen in time at the precise moment they moved there; that's what they originally chose after all. And they don't want to be forced to look at anything with a FAR above 0.4, and even that much is questionable.
Cool, figure out how to pay for trillions of dollars of sprawling infrastructure then. We in the US haven't figured that one out yet and the bills are coming due.
The more common reason people vote against it is because they want their neighborhood to be frozen in time at the precise moment they moved there; that's what they originally chose after all. And they don't want to be forced to look at anything with a FAR above 0.4, and even that much is questionable.