When arguing about the morality of landlording, defenders of landlords will often argue things not at all linked to morality. For example, “I'm a landlord because I don't want to work for someone else.” “Small landlords have their future tied up in their properties, it's literally their retirement plan!” “I spent loads of money buying those properties and put in lots of work to make them nice!”
These miss the point of the argument that landlording is immoral. The argument follows: Landlording is the practice of purchasing housing that you do not personally live in. This takes housing out of the housing market, taking away opportunity for others to purchase their own housing. Buying housing that you do not personally live in and rent to others is immoral because owning ones own housing is a basic human right that landlording deprives others.
Take slavery for example: Slavery is the practice of purchasing human beings. Slavery is immoral because humans are not property as freedom is a basic human right that slavery deprives others of. Slavers also used the same arguments, “I own slaves because I don't want to work for someone else.” “Slavers have their future tied up in their slaves, it's literally who will care for them in their old age!” “I spent loads of money buying those slaves and put in a lot of work to make their conditions nice!”
These arguments are not about the morality of the system, but rather the justification of the system from an economic standpoint. It does not matter what the economic implications of ending an immoral system might be because the system is immoral. Did slavers lose their livelihoods and investments because of emancipation? Yes. Should slavery have continued because of these facts? No. Just because one has an economic interest in an immoral system does not justify the morality of that system. Landlording as a practice cannot be anti-work or leftist and is immoral.