The end game of these libertarian fantasies is the literal wholesale murder of millions of poor "undesirables", either directly on the small scale and justified as self defense or the defence of property, or enmasse through isolation into ghettos and systematic starvation. It would dwarf the Holocaust in numbers of dead.
If you start with the premise (itself not unreasonable) that every individual has a right to defend themselves from harm and their property from theft, and you have millions of people with no ability to survive other than the appropriation of resources by force, you're going to end up with a lot of dead humans. And when the tent cities gather enough boldness and enough desperation to march on the proper cities, then you'd have the military and police slaughtering thousands at a time to protect the property rights of the middle and upper classes.
Horrifying to imagine, but there are some people who would not only be willing to go through this conflagration, but would practically welcome it. Indeed, some are even working in earnest to bring it about. They want to see the streets run red with the blood of the poor. The worst reflection I've ever had on the human condition is that some of them don't just see this nightmare as a horrible means justified by a glorious utopian end--the process itself satisfies some dark urge inside them to cause pain on the largest scale possible. If evil exists, this is it.