The people murmured because their understanding of the nature of God was totally backwards: they said he hated them, yet he loved them as his children; they said he took them out of Egypt to hand them over to the Amorites, yet he delivered them in order to give the Amorites into their hands; they said God would destroy them, yet he wanted to give them life instead.
See the kinds of things God's people are capable of saying when their understanding of him is perverted!
27 Vous murmurâtes dans vos tentes et vous dîtes: C'est parce que l'Eternel nous hait, qu'il nous a fait sortir du pays d'Egypte, afin de nous livrer entre les mains des Amoréens et de nous détruire.