It's a "job". But it's a shit career. Having to put up with destructive, unruly, and frankly unsanitary renters is a fucking nightmare.
You can live off of investment income. That's the way capitalist systems work. Don't hate the players, hate the game. Most of these "leech" landlords, are middle class people that have a slight step up, and instead of railing against the people at the top, you're complaining about the people who barely have it better than you. I get the argument, but it's directed at the wrong people.
However I am always amused at the "Don't hate the player, hate the game" comment, because invariably the people doing the hating hate both (the game that allows the player to exist, and the player for perpetuating it). It's always been a funny comment to me.
Like when you complain about a particular type of corruption in a politician (which is technically not illegal) and you get "Don't hate the player, hate the game," when the whole point is we should change the system so that politician can't be corrupt. I feel like people get lost in this idea that a person working within a bad system is inherently blameless because the system allows the bad thing (it's not wrong if it's allowed), any criticisms made must inevitably be directed at the person doing the bad thing in that system (undeservedly, hence the "don't hate the player"), and that since it's in that person's self interest to perpetuate that system it is also in their interest to treat the system as immutable.
Like, you can't have it both ways. Either you recognize the system is bad, even if you benefit from it, and it should be changed, OR you are the system and deserve to be criticized for it.