Earlier quoted context omitted.
Fear of foreign invasion is also why the Soviet Union invaded during the Winter War ("Greater Finland" irredentism was a thing, and St Petersburg was militarily exposed). Fear is why Finland allied with the Nazis. Fear is why the Soviet Union also signed a pact with the Nazis and invaded Ukraine. It's easy to justify anything with fear.
One is the biggest country on the planet, with 150 million people. The other one is about 300 sqkm with 5 million people. When in doubt, use basic logic. Your argument is the same as Iraq being a realistic threat against the US. Also, list of Russian neighbors not threatened or invaded by Russia: Belarus (pushed into a sort of union state) China (too big) Japan (I think) Mongolia (I think) Azerbaijan (I think) List o…
You've missed a few significant figures there, Finland's area is: 338145 km2