Well many of the people displacing residents don't "own" the land either. They can just afford crazier rents. The distinction between whether someone is renting or owning has little bearing on where someone considers "home".

See: entitlements people feel about going back to "homelands" in the Middle East, or to Europe after the war. These are not people that owned land, and yet we still feel morally responsible to help them return to their original homelands.

No, I don't think it has much to do with morality. Its just that some peoples won the wars and hence could return to their homeland. Do you think Jews could have settled in Israel had they lost the fight in 1948? Or Germans would have been expelled from east of Oder had they won WW2? Even Hongkong had to be ceded back to China only after China became powerful enough to leave no other alternative. Do you think UK would have given back Hongkong if China was as weak as, say, Argentina (see: Falklands war)?

Ultimately, land ownership (or its euphemisms like "homes" or "property rights") can only be backed by monopoly on violence, otherwise known as Governments, in that area.

That may be an explanation, but it's not a justification. Why don't these people own the land they live on? Keep asking why a couple more times.

Because we tried a bunch of ways to allocate lands over the course of human history. The current system (where you pay money, acquire it peacefully and the government backs your "property rights" with all the guns) seems the best among alternatives (like violence, ceding it to people who live somewhere for X years etc).

Do you have a better alternative to allocate land (or any other asset)? Please share so that we can discuss.

Public housing works quite well in Vienna.[1]

But my point was not necessarily that no one should own land. Another interpretation of my question — "Why don't these people own the land they live on?" — would be, why isn't there land around that they can afford to buy and give themselves security? And that has various types of answers, some related the kinds of opportunity in the economy that would give them more income, some about how we can change the supply of housing.

Here are some more developed thoughts on the subject from someone more expert than I am: [2]

[1] https://www.dissentmagazine.org/online_articles/case-for-pub...

[2] https://danielkayhertz.com/2017/05/11/what-is-a-left-approac...

I find the argument in favor of sunset towns in your second link rather disturbing.

The article about Vienna shows that the forces of supply and demand work very well, given an adequate supply. That seems very instructive.