Landlording is simply siphoning money through the act of owning something.

This actually applies to most all investments.

It's also not capitalism.

Adam Smith is seen as the person most responsible for coming up with the concept of capitalism, and he hated landlords.

"Landlords' right has its origin in robbery. The landlords, like all other men, love to reap where they never sowed, and demand a rent even for the natural produce of the earth."

More details about what he thought of rent in his book An Inquiry into the Nature and Causes of the Wealth of Nations.

Adam Smith imagined a world with well-regulated capitalism. In that world, a capitalist might invest in a factory to make a widget. They'd take raw materials, use capital (including labour) and end up with a product that people would want to buy. That capitalist would always have to stay on their toes because if they got lazy, another capitalist could undercut them by using their capital better, to either undercut the widget's price, or to sell it more cheaply. This competition was key, as well as the idea of the capitalist putting in work to continuously improve their processes. A capitalist who didn't continually improve their processes would lose to their competitors, see their widget sales drop to zero, and go out of business.

In Adam Smith's time, the alternative to capitalism was feudalism, where a landlord owned a huge estate, had serfs working on that estate, and simply collected a cut of everything the serfs produced as rent. In that scenario, the landlord had to do almost no work. It was the farmers on their estate who did the work. The landlord just owned the land and charged rent. Originally, serfs were even tied to the land, so they weren't allowed to leave to work elsewhere, and their children were bound to the same land. But, even once that changed, there was still good farmland. The landlord could lower the rent until it was worth it for a farmer to work the land. The key thing is that the landlord didn't have to do anything at all, just own the land and charge rent for its use.

I think the reason that people are so pissed off with capitalism these days is that what we're really seeing is a neo-Feudalism, or what Yanis Varoufakis calls technofeudalism.

Think of YouTube. A person puts tons of time and money into making a video, they upload it to the only viable video platform for user-made video, YouTube. YouTube hosts the video, then charges a big cut of any advertising revenue the video generates, basically charging rent for merely being the "land" on which the video lives. In a proper capitalist world, there would be plenty of sites to host videos, plenty of ad companies competing to buy ad spots for a video, etc. But, YouTube is a monopoly, and internet advertising is a duopoly between Google and Facebook. They mostly don't even compete anymore, each has their own area of the Internet they control and so they're a local monopoly. This allows them to behave like feudal lords rather than capitalists. There's no need for them to innovate, no need for them to compete, they just own the land and charge rent. Same with Apple and their app store. There are no other app stores permitted on iPhones, so Apple can charge an outrageous 30%.

It goes well beyond tech though. Say you're a Canadian and you want to avoid American products, but you love your carbonated beverages. You could buy Coke, but that's American. Pepsi? That's American. Royal Crown cola? Sure sounds like it might be Canadian, or British, but no, it's American. Just look at the chain of mergers for its parent company: "Formed in July 2018, with the merger of Keurig Green Mountain and Dr Pepper Snapple Group (formerly Dr. Pepper/7up Inc.), Keurig Dr Pepper offers over 125 hot and cold beverages." Sure, if you look you can find specialty things like Jarritos, but the huge brands just dominate the shelves.

Capitalists hate capitalism, they want to be feudal lords, and since the time of Reagan / Thatcher / Mulroney / etc. competition hasn't been properly regulated, allowing all the capitalists to merge into enormous companies that no longer have to compete, and can instead act as feudal lords extracting rent.

what's the difference between real estate management and landlording?

The fact that landlording is bad and not a profession isn't the point.

The point is that @MithranArkanere@lemmy.world's argument failed to convincingly argue that because it was logically fallacious:

https://en.wikipedia.org/wiki/Fallacy_of_division

In other words, the fact that thing A would "destroy of the economy if everyone did it" is an emergent property of everyone doing it, which doesn't apply to any single entity doing thing A.

This is like saying that in order for business owners to exist there have to be people who want the products that that business provides. So what?