Member nations are happy to back Ukraine with sanctions and providing weapons but that is it.
What has happened in Eastern Europe is akin to the UK invading Calais because France might join an alliance of its choice. Or re-invading Eire for the same reason. And then annexing it.
I hear lots of excuses like this, notably with domestic violence. It is not the fault of the abuser that they are carrying out abuse. It is the fault of the victim. Or someone else. The abuser claims that they were forced to do what they did, that they had no choice. But they did.
So remember, it is not the fault of Putin that Russia had a conflict with Georgia in 2008, or that it invaded Crimea in 2014, and also I am sure that it is not his fault that so many of those against him die prematurely.