I actually converted to Christianity in the wake of the Trump election, so my perspective on it relates directly to this issue. I read the Gospel without the trappings of any particular denominational interpretation, and it was abundantly clear to me how deeply problematic what had happened was specifically in the context of the Christian revelation. I'm one of those people who is very convinced that the harsh warnings in the Gospel are not actually directed at non-believers at all, and this is part of the reason why. When Christianity becomes political, we end up with false prophets and hypocrites.
I think you have a very reductionistic view on Christian history, however. You skip the first couple hundred years entirely, where we see how it reshaped pagan society, focusing instead on the authoritarianism of established Catholicism. I think this is a bit problematic, since Christianity really does challenge us to reconsider how we view stately power in the context of Christ overthrowing the powers and principalities. When considering the influence of Christianity, should we be looking primarily at variations of the religion that seek secular power, or countercultural forces that challenge society to be true to itself?
As for how Christianity can be a necessary foundation for human rights, the problem is that values like equality and universal human dignity are not actually self-evident outside of a framework that insists that humankind is created in the image of God and that salvation is available to all equally. This is not a very common idea outside of a culture that already takes it as axiomatic--much of Greek philosophy took it as self-evident that people were not equal (an idea that worked its way into medieval Catholicism with its obsession with Aristotle), Hinduism provides theological support for a caste system, and even the modern secular world rises up and challenges this assumption from time to time: look at 19th century social Darwinism.
And I think we're seeing the same thing again now with the alt-right.
This is an interesting article if you want to see a Christian take on the danger that the alt-right represents, and my own concern is that secular value systems are founded upon shifting sand and will not be able to withstand a genuine assault from an atheistic movement that can and likely will challenge the religious assumptions underpining modern humanism.
Your question was whether there was any reason that you should accept my
faith. I practice Christianity despite actually being agnostic towards it, so in this context my faith is Christianity. I think this religion is a particularly powerful vehicle of social reform (think the Quakers, Rev. Martin Luther King Jr., or even Mahatma Gandhi's flirtation with Christianity), so any humanist would be better off if they accepted it than if they did not. You are a humanist, and therefore this reasoning applies to you as well.
Theism is a metaphysical position, not a faith, and there's really no reason that you should accept it unless you think it's actually true. Anyone would benefit from an indepth and unprejudiced examination of the subject, but I wouldn't encourage anyone to just dogmatically adopt someone else's position.
You would need to explain why an eternally expanding space-time with quantum effects had to have always existed, why these quantum effects seem to be ordered so that some outcomes have higher probabilities than others, and other related questions. As long as you're positing that the nature of reality is ultimately material, you're left with the question of why reality appears to follow certain rules (unless you toss out the laws of physics and say that substances by their nature act in a certain manner, but then you need to contend with Aquinas's Fifth Way).
I think viewing ultimate reality as mathematical or informational is more promising, but then you're left wondering how mathematical truths can cause universes. Either way, I am not optimistic about non-theistic explanations.
Except that the radical equality that Christianity demands really doesn't show up in these other traditions (with the possible exception of Judaism). I actually draw very heavily upon Greek philosophy, which means that I know where Christianity is drawing from it and where it is transforming it. Greek philosophy was highly elitist.
The problem is that we agree with the moral statements that they made because we have been socially conditioned by living in a culture that accepts Christian values as true. We are not viewing this from a neutral perspective--if Christianity is in fact incorrect in what it says about equality, then our intuitions concerning equality are the result of indoctrination and ought to be reconsidered.