The Tower of Babel was destroyed and language confused because humanity was not dispersing and subdoing the earth as was commanded of them. They also would have probably ended up with technology like ours in a few centuries and by modern time would be settling different worlds which was beyond what God intentioned for mankind at that point.

Also, Judaism is not the original religion of the Israelites. It's loosely based on the old testament writings which were the words of God written according to his will by men which prophesied of Jesus and leads into what we have as Christianity today, but the defining difference is that it denies the risen Christ and relies heavily on the Talmud which is a collection of beliefs and traditions which began development around the time of the second temples construction. This religion that was distinctly different was eventually coined the name Judaism because it came from those living in Judea. The religion that Christians have was initially called The Way but the derogatory nickname Christian caught on instead.