You are missing that all jews hear that they heard from their father etc who was there! No matter how many time I and others repeat it you keep leaving that point out!
This is the checkmate.
@Aaaron, please respond directly to that argument.
Because that's an unverifiable fact! There is no corroborating evidence that the mesorah is unbroken for thousands of years, there's no corroboration that it really wasn't a made up story along the way with that bit about patrilineal passings-on being added for effect.
Some people chose to believe it.
1000 years from now all Mormons are going to hear that Joseph Smith found whatever in a field and spoke to God. Where are they going to hear it? From their fathers, who heard it from their fathers. Would it be a better analogy if Joseph Smith claimed 1 million people from 500 years ago heard God speak to them? Maybe. But the point still stands. The Mesorah we have about Har Sinai and it being passed down from father to son started somewhere. The question is, did it start at Har Sinai, or did it start later on. Again, there is 1 report of what happened at Har Sinai. If there were 600,000, obviously this would be a different conversation.
Let me know if I misunderstood the question.