there are 2 reasons. The first is obvious. Russia is much weaker today than Soviet Union was in 1947.
The second requires, for those brought up under a communist regime, a look at hard history that is not to orthodox communist liking,
The basis of the second is both Finland and ukraine was part of czarist Russian empire before the October revolution. However there the similarity in their experience with the Russians ended,
Even though the Fins were not fellow Slavs, they nonetheless a privileged minority under czarist Russian rule, because the fins supplied a disproportionate number of military officers, technocrats and bureaucrats to the czarist regime.
More importantly, Finland gained her independence with the fall of the czarist regime, and was able to retain her independence. So Finland was outside the Soviet Union during Stalin’s collectivization, so ordinary fins did not suffer the privation collectivization brought to much of USSR in 1920s and 1930s.
the only major bad experience the Fins had with the Russians were the result of the winter war in 1939-1940, and the continuation war in 1941-1945. The memory of these were bitter, but not as bitter as, for example, chinese memory of the Japanese invasion of 1937-1945.
contrast that with Ukrainian experience with the russians. Ukranians were under Russian domination, both czarist Russia and the Soviet Union, for much longer. When czarist Russians took over they immediately dispossessed much of Ukrainian nobility, for Ukrainians started under czarist Russia as an underclass, unlike the Fins.
although ukraine also briefly gained her independent]cd with the fall of the czarist regime, the independence was crushed by Lenin’s Bolsheviks very quickly, and ukraine returned to russian rule under the Soviet Union. Ukrainian farmers bitterly resisted Stalin’s collectivization efforts. Stalin ruthlessly in crushing this resistance By confiscating the harvests by force and leaving Ukrainian peasantry to starve, As a result, perhaps 25% of ukrainian peasantry starved to death. Ukrainian memory of this was bitter indeed. Equal to or or more bitter than Chinese memory of the Nanjing massacre and the Japanese “three-all” policy.
This bitter legacy is something communists do not admit because the degree of brutality the stalin committee would seem to discredit communism, but it is true.
this is a underlying reason why the Ukrainians are vat,y more hostile to accommodation with Russia than the Fins.