I read a list of the top 10 most Evil Organizations in History.

It was surprising that the Catholic Church came in #5. They were behind the Chinese Communist Party, the Communist Party of the Soviet Union (under Stalin), the Kmer Rouge and the Nazi Regime obviously, but I wouldn't have ranked the Catholic Church in the top 10 for most evil.

I guess the reason for inclusion of the Catholic Church in that ranking is Deception.
The others made no pretenses and didn't hide what they were. The Church, however, claims to help people and gains their trust, which in a way is far more devious and destructive.