"If I catch you using that thing, I have the right to respond with violence just as if you were trying to kill me"

That's just ridiculous to me. If I slap you, do you have the right to defend yourself "as if I was trying to kill you"? Of course not. Same goes from defending property. If my family is starving and someone steals the food I've worked for to feed them, then yes, it might actually be a matter of life or death. In other cases, not at all. Appropriate defensive force against an initiator of force (i.e. someone aggressing against you, someone who is being violent) is completely justifiable, when it's an appropriate amount of force. Ideally, we all use non-violent communication and no physical force is ever required.

You can say "property is theft," but until there's an alternative mechanism for determining value within the chaotic system that is human existence, I'll choose market forces over anything I've seen so far because economic freedom correlates with high levels of human well-being. Unless you're advocating we rewind the clock to the days of pre-agricultural society, property and ownership is what gives us modern society. I love open source software, and I do believe someday, maybe, we could have our needs met well enough to not have to put a price tag on everything. However, I think Steemit is an example of where market forces and the "price tag" still have great value compared to not having them. Conversations are much better here. Why is that? Because something that was previously difficult to value is now being valued by a pseudo-market force of a dollar-value vote.

It's a beautiful, wonderful thing.

I'll even upvote you for starting a good discussion, even though I disagree with your conclusion. :)