I don't think you're giving Germany its due credit for the role it has played here.
It's like Britain at the beginning of World War I. Britain didn't have a formal alliance with France, but it did have an Entente Cordial. So if Germany declared war on France, would Britain declare war on Germany? Who knows? Britain certainly didn't do anything to make its intentions clear (either to the French or to the Germans).
I think it is pretty clear now that had Britain declared unequivocally that it would declare war in support of France, World War I would've remained purely an Eastern European affair. So Britain didn't start the war. But Britain, perhaps more than any of the other players, had the ability to prevent it. And it didn't.
That's where I think Germany is today. Germany didn't start this. But Germany probably has more ability than anyone else to prevent it.
But throughout this entire sad episode, Germany has once again decided not to play a constructive role. Germany's position on the consequences of Russian aggression has been ambiguous--and I'm probably being charitable in that description. The result is that the Russian decisionmakers likely believe that Germany will not scuttle NS2, will not enforce any meaningful sanctions, and will not countenance any meaningful Nato response.
And maybe they're right. I don't know. But if the Germans had made clear that they're wrong on all fronts, I strongly suspect that Russia would not today be about to invade Ukraine.
And that's a real failure of statescraft, because Germany is going to reap a lot of the ill consequences of Russia's aggression. They're going to have to scuttle NS2, because bottom-line their relationship with the United States is more important than they're relationship with Russia. They're going to have to implement sanctions, which are going to be harmful to their economy. Worse, the sanctions that they're going to have to implement are now so unexpected in Russia that there is the very real possibility that Russia will retaliate by cutting off gas supplies, damaging the economy further. And, on top of it all, Germany will get to deal with a refugee crisis when a million screaming Ukrainians stream through Poland heading for those sweet, sweet jobs in Sachsen and Thüringen.
So, really nice fucking job, Germany--in thinking only of preserving your own prosperity, you've only ensured misery.
It's the same reason the Nazis set up a false-flag operation at Gleiwitz. It's not to convince the British and French that they were somehow justified for invading Poland. It was entirely to convince the German populace that the invasion wasn't just a naked act of aggression.
People need to think "we're the good guys." And at the same time, they're pretty easy to convince that they're the good guys. So an aggressor has to go through the step of creating some sort of pretext for an invasion. But it's not a particularly hard task.