The matter is for the Baltic States WWII did not end in 1945, as well as for the Soviet army soldiers who faced unexpected violent resistance from national partisans. The Forest Brothers actively fought the Soviet army from 1948 until the late 1950s or early 60s.
It should be noted that the Forest Brothers’ activity is little known and controversial piece of history of the Baltic States. There are two radically opposite points of view. From one point of view the Forest Brothers were partisans who continued armed resistance to the Soviet occupation of Estonia, Latvia and Lithuania after the end of the Second World War. From the second point of view such treatment of their activity is very contradictory, because there are facts that many of the Forest Brothers were former Nazi collaborators and members of the Baltic Waffen SS, and that members of these groups killed thousands of civilians in their raids. Where is the truth? I wouldn’t take the responsibility of a single answer.
It seems as if in this particular case NATO has gone about the Baltic States and puts itself in an uncomfortable position, supporting the possible misinterpretation of historical facts.
A similar dispute has become a cause of contention between Ukraine and Poland, which differently interpret Stepan Bandera's role in history. Ukraine considers Stepan Bandera a hero. Poles mainly remember him for collaborating with the Nazis and for his followers slaughtering Polish civilians. Poles find Ukraine’s version of a common history “a problem” and emphasize, that they will not accept “ideology and actions that allow murder of innocent civilians, even in the name of the highest goals, to which undoubtedly fight for state independence belongs.” The matter is very similar to what is going on between NATO and Russia just now.
Such political interference into the history of separate countries, in bitter moments of the past wouldn’t make NATO stronger, wouldn’t make relations between opponents warmer, wouldn’t make continent more peaceful. There are enough problems in contemporary history that should be solved immediately and a new one makes the situation even harder. As for the Baltic States they simply want NATO’s attention, and common Soviet past with Russia gives a good opportunity attract necessary attention and, probably, money...