So as always, it depends and there is a spectrum. The scum of the scum are scum lords, i.e. landlords who buy property, do not fix up or maintain it, fill it with any old tenant that is desperate enough to take it, well evict someone at the drop of a hat, and constantly charge exorbitant amounts on property the own outright because the protest value went up this year. It doesn’t necessarily have to be that bad, but people that buy property simply as an “investment”, i.e. get passive income from people with less money than them to buy property, are leeching off the less fortunate. There are certainly scales of badness to that, but that idea is simply immoral.

But there are other situations where one may be a “landlord” and it’s not really a moral problem. For example, a cousin of mine had to work overseas for a bit over a year and was put up in a hotel during that time. He didn’t want to sell his home, as he would be returning to it later, but also didn’t want it to sit empty. He ended up signing a year long lease over to a couple students, charged them little more than the mortgage (enough to cover the mortgage, taxes and any minor repairs that may be needed afte they left) and returned home to a house that was still in decent shape, hadn’t had any break ins, infestations, or damage from the elements, and the students got some inexpensive housing for the year. No one was taken advantage of and he wasn’t just milking poor people for profit. Everyone won. That is clearly different.