Don't forget Munich Agreement [1] that had happened a year before the respective strategic move on the part of USSR. There's no moral stance to hold against another nation's attemt to get a favourable position (for themselves) if it happens in a wake of and in accordance to their geo-political opponents' moves. The rest of Europe had been acting the same way whilst being busy preparing for a newly emerging conflict.

[1] https://en.wikipedia.org/wiki/Munich_Agreement