It should be illegal for LLCs or trust funds to purchase housing of any kind.
I completely agree that LLCs, REITs, and institutional investors shouldn’t be able to buy single family homes (and maybe even duplexes), but I don’t know about “housing of any kind.”
Large, multi family units like apartment buildings serve a vital need in the affordable housing market. Private individuals who have the capital to purchase a multi million dollar apartment building aren’t any more likely to be a conscientious landlord than a corporation. At that point, it all boils down to effective enforcement of tenant rights laws.