Are laws the only thing preventing you from stealing?

They are the only thing preventing someone less scrupulous than me from stealing.

That and getting shot.

If you're going to escalate in that direction, I'll point out that an organized group of criminals will happily escalate the issue to the point where 'Just use your guns for self-defense' is not going to end in your favor.

They'll only need to make an example out of a few people to make it clear that giving in to their demands is much cheaper than fighting them.

I have my doubts about how little this scum fears death when it's really imminent eg death row; how intrinsically lucky they are to escalate and escalate, always win and never lose; and how fearlessly they react when faced with a man who hasn't crossed the law trains his gun on them, for a legitimate reason.

If they were outside the legal system, they could retaliate in any way they see fit. You would have to commit a trail-of-tears esque genocide to claim their land

Which is exactly what people did before legal systems were accepted.