An easy explanation could be that it rankles that she was overlooked for promotion as Deputy Secretary, a job she coveted in 2021 as the Biden presidency began, and instead Kurt Campbell, President Biden's key advisor on China, recently moved in.  

The effusive praise Secretary of State Antony Blinken showered on Nuland, 62, over her premature retirement from the foreign service is usually reserved for funerals.

It is a cold war legacy that Russia hands in the US foreign service tend to hold strong views on their area of expertise. George Kennan was frequently full of regrets that his espousal of a containment strategy against the Soviet Union, as outlined in his famous 5400-word 'Long Telegram' from the Moscow embassy — followed by a second legendary contribution via an article published in Foreign Affairs under the pseudonym "X" — was completely misunderstood and turned into a militarised program of confrontation.