Judaism = Old Testament
Christianity = Old Testament + New Testament
"Judeo-Christian" just means we worship the same Jewish god (Yahweh) and the same Jewish ancient text (Old Testament), word for word. Jews are unfortunately less moral than Christians because they reject the New Testament. Which is a shame because of all the biblical figures in the Tanakh/Bible/Quran, the Good Samaritan and (to a lesser degree) Jesus were the best moral teachers of them all. Other figures like Yahweh, Moses, and Mohammad are all bad moral teachers because they all either killed many people themselves, or made rules that justified killing them. Terrible people to emulate instead of the relatively more pacifist Jesus. Who at worst, just whipped some merchants with a whip, was slightly racist to goyim (that time he nearly refused to heal woman because she wasn't Jewish), and had weird medicinal remedies (rabbi saliva was considered to be holy and have healing properties back then).
I still consider the Good Samaritan the best person you can find in the Bible. And Jesus as second best. He may have been weird, but he also wasn't homicidal like his father, Moses, or Mohammad. His moral lessons of pacificism and non-materialism are why Christians are often more morally good people than materialistic Jews or violent Muslims. While the term "Judeo-Christian" may remind you that Judaism and Christianity share the same Jewish god and Old Testament, the type of followers these two religions produce are noticeably different. With Jews often being more immoral than their Christian counterparts.
