Other than from reading all of this in a text that in part predates antiquity, how do you know all this?
Orthodox Christians--like myself--emphasize "mystery" in their practice of faith, rather than certainty. Aside from the fact that there are hundreds, if not thousands, of scholars of ancient history around the world, who have commented on these things extensively, I still wouldn't say I
know these things to be true, but like many things in life, I trust them to be true. I'm also open to adapting my way of thinking based upon new information. This is what science is all about (which I love), and I see no reason why my belief in God can't be the same way. But, for the most part, new information about the natural world does not
change what I believe about God, rather, it
informs what I believe about God. It may seem like a subtle distinction, but it is quite important. For instance, for the longest time it was understood that Earth was flat. New information was gained, and it became known that Earth is round. I would expect had I been someone living at that time that such new information would not have
changed what I believe about God, because I would still have believed (as I do now) that God created the world, whether it was flat or round, but it
informed my understanding of how God created. The same goes for evolution, quantum physics, neuroscience, cosmology, and so on.
And that's all well and good but you would hopefully agree that even though in some subjective way these things might have been acceptable to peoples of past times, they obviously have no place in a more enlightened, modern society.
The bolded is hubris on your part. Can you think of a society that, at the time, didn't consider themselves enlightened and modern? The difference with us is that we are
actually enlightened and modern, whereas societies of the past were not, right? Plus, I don't know of any Christians advocating for strict laws re:
eating shrimp, not wearing certain fabrics...and being condemned to death for working on Sunday.
Listen, the value systems of cultures change and adapt over time. It has
always been this way. It hasn't anything to do with a society becoming more enlightened and modern, but just has to do with the fact that things change--and these changes are not always for the better. In 100 years, I bet we won't even be able to recognize people--if any are left--living with the enlightened and modern values we have in 2014. But just because things will change does not mean the values we had today were of no use, or were primitive, or harmful, or whatever. They were probably quite useful for us at this time, but without a good understanding of the history and context, it will be impossible to understand why or how.
In the Christian faith, the understanding is that God is working closely with people, not absent and independently of them. Some of the things central to the Jewish culture 8,000 years ago may seem odd to us today, and don't really have a place in our current society (this is not to suggest we are better in any way than they were, we are just different) and that would make sense. It isn't that we believe God changes, but we understand that, given enough time, people do. There are certain foundational directives God has given to all people throughout all time to abide by--and even people who do not believe in a god know these things to be valid and consistent--and there are things that God gives to different people at different times, because maybe a particular context demands it. I don't think any of us should judge the past harshly, without first attempting to understand it.