Lots of different takes on this, but I don't think Putin is as imperialistic or "crazy" as he's made out to be. Much of the problem is that the US promised Ukraine (and Georgia) that they could become a NATO member. From Putin's point of view that's the US expanding their influence right up to Russian's doorstep. While the cold war is over, it's not like "the west" (broadly speaking) and Russia ever really become allies.
In a perfect world Ukraine should of course have the freedom to join NATO; but it's not a perfect world and we can't wish Putin or general Russian attitudes away. All of this could have been avoided if we just rescinded the NATO invitation (or better yet, never made it in the first place) and have Ukraine remain a neutral "border state".
I don't like Putin or Russia's attitude one bit by the way; but when the stakes are this high you really have to deal with reality as it is, not as you want it to be. Ukraine not joining NATO would have been a minor inconvenience at best; Ukraine at war is a much bigger deal, especially for the Ukrainian people. We kinda screwed them over in a game of international politics.
Ukraine could not not join NATO after Crimea and Donbass war in 2014.
Before 2014, less than 70% of Ukrainians supported joining NATO, according to polls. About 30% supported actually joining Russia, and 60% supported a union with Russia.
Everything changed in 2014, when Russia unilaterally invaded Ukraine. Less than 3% support joining Russia, and about 70% support joining NATO. After 2014, they realized Russia will never stop, so NATO was their only option (it's actually NATO that didn't want to accept them, as they worry about safety of all its members).
In a perfect world Ukraine should of course have the freedom to join NATO; but it's not a perfect world and we can't wish Putin or general Russian attitudes away. All of this could have been avoided if we just rescinded the NATO invitation (or better yet, never made it in the first place) and have Ukraine remain a neutral "border state".
I don't like Putin or Russia's attitude one bit by the way; but when the stakes are this high you really have to deal with reality as it is, not as you want it to be. Ukraine not joining NATO would have been a minor inconvenience at best; Ukraine at war is a much bigger deal, especially for the Ukrainian people. We kinda screwed them over in a game of international politics.