I think, throughout the history of humankind, it can more often than not be boiled down to this ...The world is in a bizarre place in some ways.
power, greed, control (and the desire for)
Has been this way since year dot and will forever be this way. We can't help ourselves. It's a bit of a cliché however I wouldn't be surprised if we do end up being the masters of our own downfall. Although I'm not a tree hugger, for planet earth it would surely be a positive if we were wiped in our entirety from the face of it. We're nothing but a negative on the planet. Even if nukes get dropped everywhere and we're all gone, earth would eventually recover.
And, back on topic, we can slice this situation up any way we want, blame this country, that country, this leader, that leader. Ultimately, it is Putin that decided to do what he's doing. No one else.