What is called the "Old Testament" is simply a collection the
Jewish holy books and is what they use as the basis of their religion.
They are the ones who should get hung up on creation vs. evolution, but not
Jesus didn't teach the Old Testament, he taught a new message.
New International Version (NIV)
in everything, do to others what you would have them do to you, for this sums
up the Law and the Prophets.
So, it's pretty simple, the Golden Rule equals ALL of the OT which includes
people who Christians call "great" - Moses, a mass murderer, David,
also a murderer, along with multiple marriages - Solomon 600 wives and 400
prostitutes and many other multiple marriages.
Real Christianity is practiced by many people who do not call themselves
Christianity - including atheists and agnostics.
So, "Christianity" has little to no connection with the Jewish