We have no disagreement. Clearly, the Greek and Roman empires were a key part of our "origins." But they were a key part of the origins in Asia Minor also. What made Western Civilization different from the evolution the Roman heritage took in the east was Christianity.
Of course, the influence was not all one way. Much of Christianity was, and remains, Hellenized.
Just a couple of examples, one searches in vain for any concept of the "soul" in the Old or New Testaments--that is, something separate from the body that somehow attaches and detaches from the body at birth and death but who is, nevertheless, us. So there is no support in the Bible for widespread notions such as angels with harps playing music to disembodied souls. Yet that image is firmly planted in Christian culture. It is a very Hellenistic concept. So too, Purgatory. The Hellenization of Christianity makes a lot of modern Christians very unclear on what the New Testament actually says about life after death.
"... one searches in vain for any concept of the "soul" in the Old or New Testaments--that is, something separate from the body that somehow attaches and detaches from the body at birth and death but who is, nevertheless, us." And yet, here are a few Old Testament passages one may quickly cite, passages which speak of the spirit/soul/ and body and God's interaction with spirit and soul of the individual; and these are but a few from the OT, there are many more in the New Testament and in fact the entire foundational basis for the NT is God's interaction with the spirit/soul of man! ...
Numbers 27:18 And the LORD said unto Moses, Take thee Joshua the son of Nun, a man in whom is the spirit, and lay thine hand upon him;
Job 32:8 But there is a spirit in man: and the inspiration of the Almighty giveth them understanding.
Proverbs 20:27 The spirit of man is the candle of the LORD, searching all the inward parts of the belly.
Ecclesiastes 2:26 For God giveth to a man that is good in his sight wisdom, and knowledge, and joy: but to the sinner he giveth travail, to gather and to heap up, that he may give to him that is good before God. This also is vanity and vexation of spirit.
Ecclesiastes 8:8 There is no man that hath power over the spirit to retain the spirit; neither hath he power in the day of death: and there is no discharge in that war; neither shall wickedness deliver those that are given to it.
Isaiah 66:2 For all those things hath mine hand made, and all those things have been, saith the LORD: but to this man will I look, even to him that is poor and of a contrite spirit, and trembleth at my word.
Daniel 5:11 There is a man in thy kingdom, in whom is the spirit of the holy gods; and in the days of thy father light and understanding and wisdom, like the wisdom of the gods, was found in him; whom the king Nebuchadnezzar thy father, the king, I say, thy father, made master of the magicians, astrologers, Chaldeans, and soothsayers;