As metawish said above it’s very important to know what sort of relationship you have with these people. It’s not very effective to go around making out of the blue quite drastic(for the current society) demands and expecting people to just do those things, it’s just going to have the opposite effect of cutting those people off from you.

It sounds like you’re quite young so I would suggest the answer might be nothing. Perhaps at most just sow some distrust of the very idea of landlordism or owning property in this way (sort of life real life meme magic). For instance I like to ask the open question “what does a boss even do?” (I seem to remember this comes from malatesta), an open question like this isn’t that confrontational and won’t have much immediate effect but the other person may go away and ponder over this question, they may not even come to the conclusion you’d have liked but at least they’ve have started to give it some thought rather than just presume it’s the way it always should be.

But if you really think you have a good relationship with these people where you could sit down and talk seriously to these people about the ills on society of being a landlord then go for it, but don’t expect them to change right away.