> Of course the rhetoric changed as the situation changed.
Blaming NATO is just another such rhetoric, put forward because it is the most advantageous in the current situation. It activates fools who begin self-flagellation, and in the process, disrupt military aid to Ukraine, which helps the Russian war effort.
Even among Russians who can be considered serious experts, no one takes the "blame NATO" narrative seriously. It's an excuse. A pretext. Look up Hitler's speeches from early September 1939 and you will see similar rhetoric about Germany being surrounded by the Franco-British alliance, with Poland as its spearhead. The similarity is uncanny, because it follows a standard pattern of excuses used by aggressors: portraying themselves as threatened, framing their actions as defensive, and blaming external forces for the conflicts they themselves initiate.