Other Thought
For me, and this is my personal speculation, I think the greatest evidence that Christianity is not Jewish comes in the form of what Judaism even was in the days of Christ. Namely, it was not a singular religion. What became the Judaism we know of today is primarily derived from the Pharisees. But they were only the Jewish religion in Jerusalem. Jesus was not from Jerusalem. Moreover, there were a number of other denominations around the region indirectly related to the Jewish Pharisees. There were the Sadducees, who wished to see Judaism reformed into a Hellenistic religion. There were the Zealots, who wished to see Judaism become a militant force once again. There were the Essenes, who entirely rejected the Temple and the priest and the entire sacrificial system - by far, the least Jewish of them all. There were also the Samaritans, who descend from the other 11 tribes of Israel, and various Indo-European and Canaanite peoples neighboring them. These people had their own Holy Mountain they went to, and were not called Jews at all - though they worshipped YHWH and obeyed - in varying degrees - either the Laws of Moses or the Laws of Noah. There were yet still, the Magi who came to visit Christ from the East. These Zoroastrians came to believe YHWH through prophet Daniel, and made their own pact with God through Daniel’s promises. We can see echoes elsewise, such as the Greek Titans having similar names to the Sons of Noah, and the mention by Plato and Socrates that the gods were mostly an invention of city-states trying to create stability - that there was a secret high God that the City States were trying to erase:
Neither, if we mean our future guardians to regard the habit of quarrelling among themselves as of all things the basest, should any word be said to them of the wars in heaven, and of the plots and fightings of the gods against one another, for they are not true… Then God, if he be good, is not the author of all things, as the many assert, but he is the cause of a few things only, and not of most things that occur to men. For few are the goods of human life, and many are the evils, and the good is to be attributed to God alone; of the evils the causes are to be sought elsewhere, and not in him... Then we must not listen to Homer or to any other poet who is guilty of the folly of saying that two casks lie at the threshold of Zeus, full of lots, one of good, the other of evil lots... Shall I ask you whether God is a magician, and of a nature to appear insidiously now in one shape, and now in another --sometimes himself changing and passing into many forms, sometimes deceiving us with the semblance of such transformations; or is he one and the same immutably fixed in his own proper image?... Then it is impossible that God should ever be willing to change; being, as is supposed, the fairest and best that is conceivable, every god remains absolutely and for ever in his own form.
-Plato’s Republic (Book 3?)
There are more still beyond that. Suffice to say, YHWH was not only the God of the Jews. He was well known to others, too. To declare that any interest in this God - the High God above all - to all be Jewish fables, is rather silly me thinks. But, if at the end of this text the Pagan is left with nothing but a cry that all he hates is Jewish, then I shall say all I hate is Pagan, and part ways with dealing with such an immature complainer.
A Note on the Essenes
On the Essenes, I make one final note: They appear to be the true origins of Christianity, not the Jews. For the Essenes confessed in Enoch that God is three persons, though one God:
There I beheld the Ancient of days, whose head was like white wool, and with him another, whose countenance resembled that of man. His countenance was full of grace, like that of one of the holy angels. Then I inquired of one of the angels, who went with me, and who showed me every secret thing, concerning this Son of man; who he was; whence he was; and why he accompanied the Ancient of days.