Tazemanian-devil,
Believe what you will. Last time I walked in a forest, or drove the open plains, the place was not filled with the bones of animals over 2000 years dead. Indian pottery was not laying around or easily dug up. Indian tents, moccasins, and clothing were also not to be found.
Deserts change, the sands do not remain stagnant. At one time the Sphinx was covered in sand up to its neck. Just because evidence is not found of a people spending 40 years, a miniscule amount of time, in the Sinai does not mean they were not there.
But as I said, believe what you will.