The [commemorative] events [on the occasion of the 80th anniversary of the outbreak of World War II] are an anti-Russian gathering.
Poland is the organizer of WWII and its main culprit.
This is a recurring pro-Kremlin disinformation narrative about Poland's role in the WWII.
It was Nazi Germany who attacked Poland on September 1, 1939, with Soviet troops entering Polish territory on September 17.
By the early part of 1939 the German dictator Adolf Hitler had become determined to invade and occupy Poland. Secret negotiations between Nazi Germany and the Soviet Union led to the signing of the Molotov-Ribbentrop Pact in Moscow on August 23–24. In a secret protocol of this pact, the Germans and the Soviets agreed that Poland should be divided between them, with the Western part of the country going to Germany and the eastern two-thirds being taken over by the USSR.
Read more cases of disinformation about WWII here.