The Sinai argument is popular in Jewish apologetics. A rebuttal argument can be found here. In short, other religions do make claims of mass revelation, and certain claims of mass revelation are clearly false.
Douglips:
Orthodox Jews and fundamentalist Christians will tell you that Exodus and Deuteronomy were written by Moses. Most others accept dates between 1000 BCE to 500 BCE, centuries after the fact.
Without turning this into a great debate, I think that the best rebuttal of the Sinai argument is that it is a strawman in the first place. No skeptic seriously believes that sometime around 1000 BCE, 500 years after the Exodus, some guy stood up in a public street corner in Jerusalem and said:
Hey everyone! Remember a long time ago when our people were fleeing Egypt and that guy named Moses was leading us? I’m sure all your fathers have told you the story. Well, what they didn’t tell you was that God revealed himself to the entire nation at Sinai. I know, you haven’t heard anything like this before, but trust me, it’s true.
Instead, the Sinai tradition can be seen as the development of a myth over time. Moses leads the Israelites out of Egypt. For this, he is revered as one of the greatest people in Israelite history. Perhaps he occasionally ascends a mountain to meditate. He never tells anyone what he’s doing, so the legend develops that he is talking to God. Moses also gives the Israelites certain rules to live by, which, coupled with the previous legend, makes people think that these rules are not from Moses, but from God. One day in the desert, there is some sort of weather phenomenon that the Israelites do not understand, like a lightning storm, which is interpreted as the “voice of God.” The legend grows, and as time and generations pass, it is forgotten what exactly the “voice of God” that the people heard was. And we get the Sinai story.
I’m not saying that this is necessarily how it happened. It’s just a possibility that I threw together.
Consider the story of Noah as another example of something that probably had an historical core that grew to mythic, worldwide proportions over time.
Or, as another example, consider the widespread belief that the Nazis turned people into soap in the Holocaust. Michael Shermer talks about this in his book Denying History. While enough people experienced the Holocaust for us to know that it really happened, there is zero evidence that the Nazis actually turned people into soap. And yet Shermer relates an incident with a Holocaust survivor who swore that this is true, and that she saw it with her own eyes.