Huh? Where is that indicated in the article? They had sufficient oxygen to share some with the man while they paused on their upward trek, and they obviously had enough to both continue to the summit, and then descend.
There is no indication that they could not have simply ceased their attempt to reach the summit, and used the consequently conserved oxygen to supply the dying man during an attempt to get him down to a lower elevation.
Frankly, I view this as a reasonable argument for imposition of the old tort rule that once you've commenced aid (giving a little oxygen), you are duty bound to continue with that aid in the saving of a human life, or you may be held liable for the resulting death if the death could have been prevented by the continuation of aid.
This is pretty shocking behavior.
That would create a strong incentive to provide no assistance at all.
However, what you see from this view is not the true summit, but a "false peak" known as the South Summit.
Here's what you see when you get to the top of the South Summit.
Notice the size of the climber and the limited space he has on the ridge.
How are you going to get an immobile body down that when it takes you 15-30 seconds just to lift one foot ahead of the other?
Review this thread and carefully read the detailed descriptions of how much oxygen they actually had, how it was used, and what the recipient thereof has to do to make use of it. You're missing a lot of non-intuitive details about high-altitude oxygen usage.
As for your comment on torts:
Obligatory continuation of aid does not, and can not, apply where the giver thereof needs that resource for their own survival. Resources of oxygen, heat, and even footing were already tenuous for each climber. As noted earlier: in the "death zone", each step requires serious concerted effort. If multiple teams abandonded the poor guy, I'm inclined to give benefit of the doubt to triage.
Tragic, yes. The risks and consequences were known, and the result is the reality of such risks.
Old? That's still legally binding and you raise a valid point. These mountain clymers may be subject to criminal prosecution.