There are basically two responses to immigration: the racist response calls for closing borders, and the socialist response calls for workers to be as free to move through the world as the goods they produce.
No one freely chooses to work all their life to produce capital to make others rich. The worker must be robbed of the freedom to say no, to leave, or to change the system. To maintain this social arrangement everyone, including the worker, must do their part.
Book Review: Class Struggle Unionism is based on the understanding that workers create all social wealth, and a system that allows a few to obtain billions in riches while the producers of wealth live in misery is an illegitimate system. Once we accept that reality and act as a class, victory will be ours.
The NATO nations and Russia are all imperial powers. NATO wants to expand into Eastern Europe, and Russia wants to rebuild its empire. All the combatants seek to incorporate Ukraine into their economies at the expense of Ukrainian workers.