Gentiles were excluded from Christianty for maybe a year. How long has the caste system been in place? Your knowledge of the caste system is lacking and you are not sharing the truth. The untouchables were lower class people who were not considered equals. An untouchable could not advance in society until he died and was reincarnated to a higher caste.
I don't think I have posted that Christians have not persecuted others. It seems when Christianity is discussed most people bring up how some Christians committed atrocities while ignoring the atrocities committed by men who adhere to other religions.
You are correct every religion has people who stray from their historic roots. However, not every religion evolves over time and adopts societal and cultural mores as the norm.
Biblical truth has not changed since the inception of Christianity, although false teachers have attempted to change what it teaches. The same cannot be said for Hinduism.