Comment by sam1714

Similar to why there's a significant fraction of pro-mainland China people in Taiwan and Hong Kong.

Reasons include people who benefitted from the Soviet Union, often due to business and trade. Analogy would be Foxconn, a Taiwanese company which is dependent on manufacturing in China.

Nostalgia/rose-tinted glasses/rosy retrospection, Ostalgie in German.

Families that were ethnically from Russia, moved during the Soviet Union times and still have ties to Russia.

The former East Germany is way more pro-Russian than the former West Germany, showing the effects of these factors.