There's two ways to interpret what is going on when one side is engaged in actual use of agents of force to obtain an objective and the other side, with the same or better force capabilities, does things like merely warn the force-using side to stop, or else...

The wrong interpretation is to imagine that anything new, like a new surrealpolitik paradigm, has infected the thinking of the non-aggressive side, which is what I see all over the blogosphere, like in your blockquote here.

The right interpretation is that the NATO side has already determined that use of force in Ukraine is not worth the effort, so it is writing the Ukraine off but cannot tell that to their allies in the Ukraine and elsewhere because it sounds too ruthless and unsupportive of justice, democracy, and the rule of law, the shared values for which any use of force must be consistent in the first place.  In Realpolitik, when someone uses words and official statements rather than actions, it is code for: you're not that important to us right now.  No one should infer from this that policymakers on the NATO side have a different view of reality at all.

As a young community organizer in Chicago, President Barrack Obama used to lead intense organizer trainings, called "week-longs" where trainees learned to abandon the "justice junkie" mindset and adopt Saul Alinsky's unique style of Machiavellian street politics. The week's training begins by reading Thucydides' "Milean Dialogue," the core text for the Realist school of international relations. The exercise that Obama, like all trainers then, like now, taught was to divide the trainees into the Melians and Athenians, and let them try to negotiate an outcome.  One of the key lessons was to not think like the stupid, self-righteous, but sympathetic Melians, but to think instead as ruthlessly and strategic as the Athenians.  Don't waste your resources on something where you can't build power as an outcome.

I really doubt Obama has forgotten this formational part of his entry into politics. Nothing else he has done indicates that he has. I'm pretty sure the US and NATO just aren't seeing where it helps them build power to get involved militarily in  Ukraine at the present time, or they would have already done so.