> They can be repaired - but if you think they can't be, then the US should act accordingly which would mean yea go ahead and take over Greenland, withdraw forces from Europe, &c. because as you say they can't be fixed so we might as well do whatever we think we want or need to do - that's the chain of reasoning that this theory of unrepairable relations sends us down.
Irreparable doesn't make it a good idea to increase the damage, in much the same way that a company losing their trademark ("irreparable harm") can have an even worse time if all their banks suddenly refuse to do business with them.
The US taking Greenland by force means either NATO ends, or it collectively is at war with the USA, either outcome within a week or less. Similar but with different timelines for the entire EU due to Article 42(7), even though not all EU member states are in NATO and vice versa. It means maximally escalating trade prohibition (which doesn't mean everything from day 0) rather than simply the absence of deals leading to tariffs.
I will note with Suez, the British and French were humiliated, and by some the crisis is considered to be the end of the British empire. The British are not exactly beloved world-wide, despite what British newspapers will write about all the asylum seekers.
And the French didn't fully withdraw from NATO, but from the US-led unified command and the control of NATO's nuclear arsenal, to approximately quote the Wikipedia page.
Neither world war worked out well for those involved; for the British it was two Pyrrhic victories in a lifetime, for Germany it was humiliation and hyperinflation the first time around and getting quartered the second time around with active economic suppression only ending because of a proxy conflict of brain drain across what became the Iron Curtain. In both wars, Germany was seen as villainous for the next generation. The relative economic damage in Europe is what allowed the USA to become a superpower, and it only really supported Europe as a foil against Communism.
Or just look at how much the borders changed going from pre-WW1 to post-WW2.