My gut-level response would be to say why donāt you accept Jesus as the Messiah? I mean, the New Testament is a far more reliable history than the Old Testament, which, if not for the authority of the Catholic Church recognizing them as inspired and true Scripture, I would probably have a hard time accepting them. So, if it is not on historical grounds that you donāt accept Christ, what?
My second gut-level response would be that modern day Judaism is a man-made religion much like Protestantism. A lot of Old Covenant Judaism is simply done away with for one reason or another - Rabbinic texts from which modern day Judaism is based are filled with loopholes and other attempts on how to bypass Old Covenant practices and norms. And like Protestantism and Isam, there is no legitimate authority from God that backs up any of these things. Without this authority, there are a lot of internal inconsistencies, which, like Protestantism, leads to chaos. There are multiple sects of Judaism, there is no cohesion or continuity between them or between Old Covenant Judaism and today. Such cohesion and continuity only exists in the Catholic Church.
My third gut-level response is what reason is there to think that Judaism is the true religion in the first place? We can arrive at monotheism through reason alone, but why Judaism? What motives of credibility are there for modern day Judaism? The Old Testament history is so old, that it can only be broadly and vaguely supported - there is nothing specific, unlike the figure of Christ, that we can point to and say āYup, Judaism is true.ā But even if we do find such a clincher, we still have another hurdle to cross, since modern day Judaism is totally different animal. What makes that true? Is its legitimacy supported by many miracles, like the Catholic Church? I donāt think so.
If I were to place myself in the atheist position, work my way to monotheism through reason alone, and try to discern which religion has the true Revelation, there simply is not much, if any, that support Judaism. Itās only the Catholic Church, with its smooth continuity, cohesion, holiness, and miraculous history that stands out.
Iāve been meaning to learn more about Judaism, though. I could be wrong on all of the above, but those are my āgut-levelā reactions.