People extorting money due to the finite nature of land, for the sole reason of having been born with better access to capital.
It's just making money, due to having money. They didn't invent anything, they didnt discover and invest in an emerging company. They didn't do anything innovative or clever. Anyone born to wealth could have done it. Which is why those are, by far and away, the vast majority of landlords.
Even a Conservative, union busting aristocrat like Churchill knew how bad landlordism was and landlords have been hated throughout all of human history. It's only the current neoliberal plague who've attempted to moralise it with rich people worship and bootstrap paradoxes.