Earlier quoted context omitted.
And the USSR undertook the greatest ethnic cleansing of the 20th century in response. Should they apologize for that?
The USSR ethnically cleansed Germany in response? What? Or do you mean something else? Had Nazi Germany prevailed, it is estimated about 30 million of all Slavs in Eastern Europe would have been cleansed, as per the stated goals of Generalplan Ost [1]. Getting rid of "undesirables" and "surplus population" on one of the widest scales mankind had ever seen was one of the main goals of Nazi expansion. They started to c…
https://en.wikipedia.org/wiki/Flight_and_expulsion_of_German...
In particular, postwar Poland basically moved west: the Soviet Union kept the 77.6 thousand square miles of Polish territory it had captured when both Germany and Russia partitioned it in 1939, while Poland was given 48.1 thousand miles of German territory. The Soviet-backed Polish government cleansed the formerly-German territories of ethnic Germans.
Given the far worse behaviour of Germany during the war (I believe most Germans survived the ethnic cleansing committed by Poland, while the goal of Nazi Germany was extermination of the Poles), it can be a bit difficult to care about the suffering of Germans. But consider that IIRC roughly two million Germans died in the expulsions from Poland and other countries, and no doubt at least a few of those were innocent women and children (as, of course, were many of Nazi Germany's victims). Two wrongs do not make a right, and mass murder of innocent civilians is always wrong.