The definition of "make a living" is highly subject to preferences. The vacant houses are in areas where other people live. If those other people can't make a living, then shouldn't we improve the economy in that area rather than ship those people off to more congested areas or leave the homes vacant?

I believe that poster is using "preference" in the economic sense: https://en.wikipedia.org/wiki/Preference_(economics)

"In economics, and in other social sciences, preference refers to an order by which an agent, while in search of an 'optimal choice', ranks alternatives based on their respective utility." "Individual preferences are determined by taste, need, ..., as opposed to price, availability or personal income."