Russian Orthodox Church praised occupation of Poland, blessed imperialistic monuments of occupation in Warsaw with words of encouragement toward Russian Imperialism, and supported discrimination of non-orthodox people in Russian Empire.
There was not notable discrimination towards non-orthodox people in Russian Empire. Discrimination against Jews was also based on their status as visibly strange outsiders speaking the weird Yiddish language. The Orthodox Church specifically rejected to spread their religion to the Turkic and Mongoloid peoples eastward. Catherine II accepted religious pluralism in Russia, seeking to create a Muslim hierarchy.
There was not a Russian occupation of Poland. Rather, through various wars traced to Polish aggression in 1609, Russia, as Catherine II explained, preoceeded to liberate primarily Ukrainian and Belorussian territories which were stolen by Lithuanians in the 14th century. If you consider the presence of Poles in Russia to be an "occupation" even though this so-called Polish territory was in fact Ukrainian and Belorussian, then the Polish-Lithuanians occupied East Slavic Orthodox territory.
If you want to talk about religious discrimination, refer to Poland's mistreatment of Orthodox Christians. Forceably, the Orthodox Church was brought under the control of the Pope which angered the East Slavs. In a 1689 treaty signed between Russia and Poland, Poland finally promised to stop oppressing the Orthodox population living in Belorussian and Ukrainian provinces. In 1596 the Union of Brest-Litovsk subordinated the Eastern Orthodox church of the Commonwealth to the papacy by creating the Eastern-rite (Uniate) church. Politically, this was intended to cement the cohesion of the state vis-Ã -vis Moscow; instead it led to internal divisions among the Orthodox. The new Eastern-rite church became a hierarchy without followers while the forbidden Eastern Orthodox church was driven underground. Wladyslaw's recognition of the latter's existence in 1632 May have come too late. The Orthodox massesâ€”deprived of their native protectors, who had become Polonized and Catholicâ€”turned to the Cossacks.
Source: Encyclopedia BrittanicaBut this was the very misfortune that the Ruthenian nobility, this very Ruthenian higher class who was benefiting from being under the power of Poland, was not able to hold to its own from the moral oppression, that was burdening the Orthodox religion and the Ruthenian ethnicity. Entering into the relations with the Polish Szlachta, adopting the Polish language and Polish habits, the Ruthenian people were not powerful enough to hold on to their forefathers' religion. Catholicism was supported by the eye catching shine of the Western enlightenment. In Poland, the Ruthenian religion and the Ruthenian ethnicity were looked down at: everything resembling Ruthenian seemed to the eye of the Polish society as rustic, vulgar, savage, ignorant, something an educated and upstanding citizen should be ashamed of. Catholics had much better means for education and, therefore, the children of the Orthodox nobility were taught by the Catholics. Stirred up by their teachers, who indoctrinated them with the reverence to Catholicism, entering the court, where they in the prevailing propaganda spirit only heard about the same reverence, the Ruthenian youths inevitably adopted the same attitude towards the religion and the ethnicity of their forefathers, as usually common for those who draw on the alienation under the full conviction that the alien is the sign of education and gives the honor and respect in the everyday life which they are to be part of. The converted to the Catholicism descendants of the noble families, looking back at the morality of their forefathers found themselves in the same mood, as their ancestors who abandoned the Paganism and adopted the Christianity many centuries prior to that. One after the other they adopted the new religion and felt ashamed of the previous one. True, as it always is in the transitional periods, so was in the period of Catholicization of the Ruthenian nobility, for as long as half-a-century, or sometimes even longer, there were remaining adherents of the old tradition and they made themselves heard, but those were becoming very few and far between, and finally there were none.http://www.kulichki.com/inkwell/text/sp ... stom22.htm
Morever, it was the Catholic Church which supported the vicious imperialism practiced by the French, Portuguese, and Spanish. The Catholic Church supported fascism in Italy and Spain.
Of course in modern times Orthodox religion is present only in very underdeveloped countries with little influence on world affairs and among a handfull of people(I would be surprised if it is worshiped by more then 100 milion people in reality), so nobody really cares for it much.
That is incorrect as Russia is a permanent member of the UN Security Council meaning that the permission of Russia is required in order for action to be taken. Russia's enormous military strength and natural resources render it a superpower. The characterization of Russia, Ukraine and others as "underdeveloped" countries is a misunderstanding as Russia is an advanced industrialized, urban country. In Europe, there are more Orthodox Christians than Catholics.