I am not saying Habitat for Humanity (or any charity) is bad, nor am I trying to discourage anyone from giving to charity. I'm pointing out that what works in a small scale charity does not work for addressing social problems at scale, and in fact is often (more often than not) harmful when done at scale. This is because the specific things that charities are good at: giving stuff to small groups of people, is not really a path forward for problems faced by society as a whole, with the exception of the problem of poor people not having enough stuff. But when you try to use this approach for, say, housing policy, then you get bad outcomes.
We have had in this country a long term, bipartisan consensus that home ownership should be subsidized. The end result is transfers from renters to home-owners, record high homeownership rates, and many people buying homes because it's a way to make leveraged bets on asset prices at taxpayer expense. There are many people who have no business owning a home but who feel they must do so in order to not be left behind in this game of leveraged bets. The result is a toxic tangle of cross-subsidies between the real-estate and financial sectors and a whole army of various parasitical industries that has sprung up to feed on these subsidies -- everything from real estate brokers, title insurers, inspectors, appraisers, a virtual caravan of people lined up at the trough of our housing subsidies, all in the name of "helping the middle class" afford homes.
When you have such a terrible problem of mispricing and people chasing after windfall gains, the idea that the industry should be approached as a type of charity is really the last thing you want to do. If you want to give money to a poor person, then by all means do so, but that's not a path forward for national housing policy.