All of those countries joined NATO because they themselves wanted to. No one forced them to do so.

Everyone near Russia wanted to join NATO as quickly as possible because they were deeply worried about Russian invasion, having been invaded by Russia in the recent past, and given that Russia historically has always been territorially expansionist.

Ukraine couldn't get in. Ukraine has been invaded.

Georgia wasn't in either, and they were invaded as well.

If I were anywhere near Russia, I'd start connecting up with my neighbours in a defensive alliance, too, and this brings us to a critical point; NATO is a defensive alliance. The treaty says each country considers an attack on a fellow member to be an attack on itself.

If any NATO country goes off an invades another country, of its own accord, its on its own.

Russia is not threatened by NATO, but Russia is stymied by NATO, because it blocks Russian territorial expansion.

Russia of course also has its long history of propaganda and double-think; black is white, weak is strong, aggression is defence.

Finally we must note the appalling sadism of Russian military forces in occupied territories, and of the Government toward the people of Russia.

Only one country is fully responsible for this war, it is the one that invaded a sovereign country under false pretenses. Russia has been openly gearing up for war for quite some time, NATO expansion as an excuse to start a war is just propaganda.