tn The question is rhetorical. It was not a small thing to them—it was a big thing.
tn The modern scholar who merely sees these words as belonging to an earlier tradition about going up to the land of Canaan that flows with milk and honey misses the irony here. What is happening is that the text is showing how twisted the thinking of the rebels is. They have turned things completely around. Egypt was the land flowing with milk and honey, not Canaan where they will die. The words of rebellion are seldom original, and always twisted.
tn The verb הִשְׂתָּרֵר (histarer) is the Hitpael infinitive absolute that emphasizes the preceding תִשְׂתָּרֵר (tistarer), the Hitpael imperfect tense (both forms having metathesis). The verb means “to rule; to act like a prince; to make oneself a prince.” This is the only occurrence of the reflexive for this verb. The exact nuance is difficult to translate into English. But they are accusing Moses of seizing princely power for himself, perhaps making a sarcastic reference to his former status in Egypt. The rebels here are telling Moses that they had discerned his scheme, and so he could not “hoodwink” them (cf. NEB).