> The idea that slavery is wrong or women should have the right to vote never got less accepted over time.

This cannot be the case, because those ideas have not existed since the beginning of time. They had an origin and therefore an upward trajectory towards their reification in law.

With a scant few matriarchal societies aside, most of human history is absolutely dominated by men making other men and women subservient to them. That's the story of humanity.

This is very wrong. Various cultures have had different systems of slavery - some better, some worse - and vastly different views of women's civil rights or participation in society.

I don't think so. I think that the societies that practiced slavery were always amenable to the practice. The societies themselves just grew and spread.

For example: Iran's official policy went from being progressive to oppressive, but it was a result of the Islamists moving into power in the 70s. They didn't just suddenly convince everybody that "hey we should oppress women". All of those people were there, and had been there for a long time. They just weren't in power.

To pick a glaring example, what about American slavery? Do you think there was an unbroken line of racist slavers from the dawn of time right through to Eli Whitney's cotton gin? The fact is, slavery was made much worse because of the economic situation after the invention of the cotton gin.

It's not as if Americans were abolitionists until the cotton gin was invented. The justification of slavery was already there. The institution of slavery grew due to the cotton industry, but those people already had the justification they needed. They knew the Bible didn't condemn slavery and they had God on their side. Abolition spread in spite of the economic demand for slavery.

I couldn't figure out how to efficiently say exactly what you just wrote. Nicely put!