That's simple: they're weak and can't get away with it. The baseline conduct of nation states is basically that of fairly rational psychopaths, capable of evaluating what they can get away with. Deviations from that norm are mostly reminiscent of irrational psychopaths. Anyone who expects "moral", "just" or "trustworthy" behavior from a nation state is just out of their mind.
Some would say “submitted to” rather than “withstood”; heck, accommodating a powerful neighbor out of fear and inability to effectively resist is called “Finlandization” for a reason.
Eugenics: http://eugenicsarchive.ca/discover/tree/530b988476f0db569b00...
Kekkonen and the collapse of democracy: http://www.nytimes.com/1973/01/18/archives/finns-extend-pres...
Only after they came to a stalemate and peaceful agreement with the USSR did they split from the Axis and align with the Allies.