My grandfather died in soviet gulag camp. I hate communism and soviet system!
Some 60 million people (the vast majority of them ethnic Russians, Belorussians, and Ukrainians) perished during Stalin's reign. Some of them were exterminated in purges, some perished during the warfare, and the rest lost their lives in famines and epidemics. There is hardly anyone in the former USSR, who has not been affected by Stalin's crimes.
Yeah we always learn (in Europe at least) how the third Reich was the worst thing ever, but even if 3rd Reich was horrible it killed and destroyed less than USSR or Mao.
Even if, to be honest, it last much much much less xD
But I don't think it's a reason to hate communism though. Communism has been tried four times in the whole history and gave a good result (Cuba) whereas capitalism has been tried and used for thousands of years and still doesn't work! Maybe we should try communism/socialism again.