I used to place great importance in these NATO issues a year ago. After Putin invaded, I realized NATO is a red herring.
Not once in your story did you mention oil or gas. You recognize that whoever controls Ukraine controls the gas lines running across it and its new found reserves?
Does the consumer of oil/gas have as much of a right to the oil/gas fields as the producer of the oil? Russia says no.
Most of the struggle with Russia is over natural resources. Would you want your 401K invested in an Autocratically (KGB mafia) controlled oil field or democracy controlled? Put yourself in the shoes of the people who bring you your energy.
Western Oil companies use their governments (military) to protect their overseas interests. They don't really care who is in charge as long as they feel their interests are secure. Look at the Kingdom of Saudi Arabia. It does stuff to make it look like it is independent, but when it comes to its oil and security, the West has full control. Without U.S. protection, Iran could run roughshod over Saudi Arabia tomorrow. The KSA has advanced U.S. weapons in their hangars but no real military force. What they get is rich (leaving aside all those who don't).
I mean follow your own logic. Why should NATO care who controls Ukraine? As others have pointed out, you gloss over the fact that Ukrainians care!
Some random comments:
Should the U.S. allow a leader of Russia who keeps threatening nukes to stay in power? I dont' know about you, but I'd like him assasinated tomrorow. I'd want the same for a U.S. President who said the same things. Destroy U.K. with a nuclear torpedo?
If we let Russia take Ukraine, then what? Putin's regime then takes all the new oil/gas reserves, puts more money (from us) into its military, and becomes even more powerful and difficult to control.
Putin is mortal. The regime will change. Worries that his replacement might be better has little to do with how it happen, through his natural death or a hellfire missile.
I think it's well understood, at high levels, what Putin/Russia's reasons are for invading (many of which you have painstakingly gone over). However, the use of force is not proportional to these security interests, it is unhinged.
Russia is notoriously corrupt. Should we lose sight of that when we talk about what was promised to who and why?
The countries that joined NATO didn't do so with a gun to their head. They chose the better offer. Russia lost. We can't all get what we want. Yes, the U.S. will bully countries that leave its orbit. It did that to Iraq. However today Iraq is probably run by Iran as much as the U.S. We don't care. As long as the oil fields are protected and the money not used to change the petro-dollar etc.
What do you mean exactly about U.S. support of the Maidan protests? This is a lot of conspiracy talk which infantalizes Ukraine. If you're Ukrainian and you took a banner printed by the U.S. and went out and protested do that mean it was U.S. lead?
Russia would never set up an alliance with Canada because Canada has nothing Russia wants. Again, the West is a primary market for Russian oil. That's why we're there.
Simply put, Russia is using our (consumer) money to take land by force. They might get away with it; they might not. But it has little to do with NATO.