The whole thing does strike me as morally irresponsible in that a city with a persistent and undealt with homeless problem should not be limiting the availability of housing units until the blatant market failure has been dealt with.
Red herring. These people are not inviting the homeless into their homes. They are operating a hotel/B&B without following any registration, safety, health, or tax rules.
It is a related question, there are plenty of people with marginal housing arrangements who live in weekly rate motels for more than half of each year; paying more for housing that would cost them less if they had the economic stability to rent those same rooms by the month. So at the margin, the availability and constraints on the supply of housing units do directly affect some people who are homeless.
Red herring. These people are not inviting the homeless into their homes. They are operating a hotel/B&B without following any registration, safety, health, or tax rules.