That clearly wasn't the point they were making, they were just explaining why your suggestion of "only make it show to people who search for a specific address" doesn't do anything to limit the ability of landlords to look up reviews about themselves.
It does though. It eliminates the need to ever include an address in plaintext on the site, making it a lot harder for data harvesters to extract private information from it. Landlords likely won’t iterate through each and every similar site to search for reviews. At least not all of them.
Bcrypt has key stretching, brute-forcing every address in existence would cost a lot of CPU even for one city. How will the attacker get compensated for that?