I'm sure you're just being silly, but ok. Take what you can. That is pretty much literally how it works. I'm not stopping you.

You say that now because you don't believe it's possible for someone to capture a large enough quantity of oxygen to impact you.

If that were to change, which it may, you would feel differently.

It isn't just that I agree, but that I just wrote long - excessively verbose, I thought - posts upthread and downthread explaining how I expect the situation would play out, how it would affect me and how I'd respond to it. What more do you want from me?

It's a fact that, right now, the dude can use whatever amount of air he feels is appropriate for his circumstances. Even if I wanted to interfere I doubt I'm even on the same continent as he is, and it isn't my business anyway.

Where can I buy oxygen rights?

I recommend Amazon. You can buy a tanks of the stuff to call your own if you feel like paying someone something.

There'd be specialist companies that do bulk oxygen supplies too, a quick search found things like https://www.dswgascylinder.com/product/liquid-oxygen-trailer.... Not a market I'm familiar with.

I suppose I'll just add in postscript; your not going to get much out of the conversation if you don't take it seriously. There are people who make great money selling oxygen. It isn't automatically priced at $0. In some hypothetical world where quality oxygen wasn't just floating around in the atmosphere, people would pay for it in the same way they pay for other essentials like food or water. Paying for water is about as crazy as paying for oxygen, they both basically just turn up out of the atmosphere. And there is precedent for a commons essential good becoming more expensive, food used to be something people just picked up off the ground for free. Or hunted down on unclaimed land.

So I'm only allowed to breathe the oxygen I buy in tanks?