Why should I ask myself, I'm not the one saying Russia has anything to fear from Nato. I dont think they do.
I do on the other hand think Russia and Putin fear USA, and by Nato expanding more to the east, they feel like USA is more or less expanding its boarder against them. I think Putin and Russia are very concerned about this, and in no way believe the reasons being said publicly behind it. Countries are often paranoid about these kind of stuff, and dont trust what their enemies say their intentions are. Just like Americans dont trust Russia and China, they dont trust Americans.
I agree with you that Russia are acting like twats. What you fail to consider, is that from Russias point of view, they dont think they are the ones acting like twats. They think USA are the twats, by expanding their territory (thats how they see Nato) against them. From their point of view, USA is not the hero, the world police, who intervene in every countries war and brings order and freedom to the world. From their point of view, USA is the villain, bringing death and destruction all over the world in conflicts they have nothing to do with.
I'm not saying they are right, I'm just saying that Russia see themselves as the good ones, and USA as the evil.
Not the other way around as we do.