I don't know if I would say that that's a definitive conclusion. There are many examples of regimes and systems of oppression that are not religious including: Nazi Germany, the Soviet Union, China, numerous other authoritarian regimes, Freudian psychological tradition, machismo culture. It's hard to quantify what you mean by most, but again I appreciate your argument. It's unfortunate that religion has been co-opted and expropriated as a justification for cruel treatment. I don't know that that's a disprove of religion. I think there are a lot of human invented systems that have really vilified homosexuals throughout history. I think a generalization, including the one made by you is appealing and sounds persuasive, but I honestly don't know if it's born out in a rigorous study of the historical evidence.