The Russian Federation likely would not give NATO or the US more fuel and pretext. And that would not help them maintain the image they are trying to project to the world. Honestly the Kremlin knows Americans are not the problem and other than vetting for foreign agent BS, they would rather use the being kind to Americans refugees propaganda angle more. Nothing would make the US look worse than Americans escaping there for safe haven. There is already information about Americans moving to Russia and there are expats there to stay.