It should be noted that the Old Covenant and the New Testament are not outright the same canon. Whenever someone says that "The Bible is full of contradictions", they're usually referring to something said in the Old Testament, that was changed, revised, or rescinded, in the New Testament.
The way I personally see it is that the Old Testament is meant to be some kind of proto-history textbook, with a few stories and allegories that may be important lessons for people to learn as they grow up and experience life, as well as to provide context for the literature that the New Testament provides. Christians, as of 0 A.D., do not sacrifice livestock, harvests, or people, for example. Jews did.
Modern-day Jews are also absolutely nothing like historical Hebrews, at all, as well, and I'm not just talking about their genetic lineage. The Old Testament is a mere fraction of the content in the Torah, and the Torah is but one of 3 major written works (The Talmud, or if you're really spicy, Kabbalah) that Jews read/follow. It's called the Old Testament for a reason. It's outmoded, and is in conflict with the Christian New Testament, and the expanded neo-Jewish works.
Jews aren't even consistent on which entity God is to them, anyway. El/Elohim (The One, The Name, with Elohim being plural) was their original diety, which is of Canaanite origin. YHWH, on the other hand, is the Lord of the Hebrews, and, at least initially is/was a separate entity from El in their Pantheon from the Canaanite Era. There are numerous interpretations of this, also. Modern Judaism treats them both as the same thing, but they are not, historically speaking. In the most literal translation of Genesis, El refers to himself as "we", and "our", during the Creation period. Not singularly.
(Genesis 1:26-7): "Let us make humankind in our image, according to our likeness; and let them have dominion over the fish of the sea, and over the birds of the air, and over the cattle, and over all the wild animals of the earth, and over every creeping thing that creeps upon the earth."
(Genesis 3:22): "See, the man has become like one of us, knowing good and evil; and now, he might reach out his hand and take also from the tree of life, and eat, and live forever"
What does all of this mean? Probably nothing, possibly everything. Depends on what you believe. Personally, what I take from that, is that the New Testament is the thing Christians should be paying attention to for moral guidance, and explicitly not the Old Testament, although the inclusion of the Old Covenant is important context material. The Atheist takeaway is more than likely, "why would a perfect God have to change his holy book to reflect a new age of man?" The answer is in that hypothetical quote. Humanity changed. God himself, may or may not have.
I find the whole thing very fascinating. Too bad that fascination comes with a heaping dollop of existential dread.
