As the article above shows, multiple verbal assurances were given, in response to concerns voiced by Russia about NATO expansion. If those concerns were unfounded, why were the assurances given?
To get them to shut up and sign something - the agreements with the signatures are what nations are held to, and there's nothing about not allowing countries to join NATO as a protection against potential Russian militaristic expansion. Just like those 'concerns' that were voiced weren't actual concerns for security, but perceived threats to Russia's local influence and desire to rebuild the Soviet era empire once more.
The point is though, our current actions are based on the assumptions, firstly, that Hitler would have continued invading other countries if appeased,
No, they're based on the demonstrable history that Hitler made agreements with various nations trying an appeasement approach, and he repeatedly then broke those agreements and expanded again. It's not what if he had, it's that he did.
and secondly, that Putin would do the same.
Are the previous seven, eight, nine military interventions in foreign nations that Putin has authorised not a sufficient indication of his intent? How many chances do we need to give him? Even if this was going to be his last one, what of the Ukrainians who, and I can't believe that I need to be reiterating this, don't want to be Russians, and so voted accordingly?
But Putin knows the line he can't cross, that is, invading a NATO country.
For now, at least. Which is why he reacts when nations look to NATO, because it takes those nations outside of his reach.
Also, from listening to Putin's speeches: although they are long and rambling like Hitler's, he doesn't talk in such a murderous way, so another assumption, that Russians would commit genocide if their security demands had been agreed to, is not reasonable.
Their 'security demands' are both not about security, and not reasonable. Russians are already committing atrocities, and have a history of doing so in their other too numerous invasions of foreign states in the last two and a half decades.
O.