Finland was a nazi ally. USSR wasn't.
Go read that so-called "secret protocols". Then look on the map. Think a little. Try to grok what's wrong
/*I
do know what's the trick, but reading the actual "document" may be really eye-opening for people who turn on their critical thinking for the first time*/ Hint: "Northern border of Lithuania".
I understand that you are protecting that so-called "baltic states" because if USSR didn't take them in 1940 - then nazis could use them as a beach-head against Leningrad, so Finns could remain in Karelia in case USSR lost a war.
I admit that Finnish war was an act of aggression committed by USSR, but you have to understand that all Soviet pre-war politics was aimed at survival.
"Наша ближайшая задача - сделать всех..." (с) И.В. Сталин