In 11:21-24 the passuk relays a conversation between Moshe and Hashem. Moshe says there are 600,000 people here and how can You just say You will give them meat for a month! Even if You shechted all the cattle and brought them all the fish from the sea it would not be enough for a months worth of food! So how can You make such a promise?
It seems that Moshe also doubts Hashem's ability to provide and to come through on His promises. So what makes MOshe better than the rest of the Jews, that he is their leader?
According to the Sifri brought in Rashi, this question only applies according to the explanation of the passuk given by Rabbi Akva who understands it according to the simple meaning, as I described it above. According to Rabbi Shimon there is no question because he understands it differently.
So, according to the simple reading of the passuk, and according to Rabbi Akiva, how could Moshe have these doubts, and if he did,what made him better than the rest?
People are allowed to have questions. Having emuna, faith, in Hashem and the Torah does not mean one cannot have questions. It does mean that those questions do not sway his observance of the mitzvos and following Hashem's words.
So maybe Moshe did have questions and doubts. Maybe he did not understand how everything worked. But Moshe had emuna and he acted on the emuna and not on the questions. The rest of the people kvetched and acted on their questions. That is the difference.