Contrariwise:
If high density living reduces society's environmental footprint, then it's using less raw resources and drawing less power per person housed.
Helping people who operate high density residential charge more for it, per person, is literal price gouging and extracting unreasonable profit.
There should be a good return per high density housing project from the fact that there are more people overall, but the expectation, surely, should be that total cost per person housed is less and that profit per person is accordingly also reduced.