And the people quarreled with Moses and said, “Would that we had perished when our brothers perished before the Lord! Why have you brought the assembly of the Lord into this wilderness, that we should die here, both we and our cattle?"
Irrational complainers say really stupid things. Grumbling is usually dumb. For instance, in their complaining, the Israelites consider those who died in direct judgment by God as now better off than those alive in the wilderness. They are basically agreeing with past rebels and wishing they had joined them! They'd rather be dead sinners than live followers of the Lord in the desert of Sinai. This is a really moronic proposal to bring before God as they fought with Moses!
Their quarrel is with Moses as leader but really their rebellion is against God Who literally led them to Meribah with a pillar of cloud and fire. They don't like the prospective difficulties of living in the desert even though all the way up to this point God gave them manna and provided water and protection for their every need. When their current campsite has no easy water access, they immediately complain to Moses, even though God had led them to their current place in order to display His power.
There is no logic to complaining. The Isrealites just go on with their negativity and attack their leaders without thinking. They express two mutually exclusive complaints in their dangerous emotional grumbling: 1) Those who died already are better off even though they died in judgment on their sin. 2) "we are going to die now and we don't want to!" I'd have this incredulous reply to them: "So do you want to die or don't you, because you are saying both?!" It's hard to understand their complaints because the "insights" exclude each other! But really grumbling isn't logical. It's raw pain being expressed in complaint.
Sadly though, this was the complaint that drew Moses into unbelief as well. He disobeyed God's command and struck the rock at Meribah rather than speak to it as God had commanded. That God gave any water at all is pure grace! Moses, by entering into the disobedient attitude of Israel was then denied the last victory of his leadership to bring the nation into the Promised Land. Complaining has serious repercussions. Divinely orchestrated circumstances arranged by an infinitely wise and holy God should not be lightly dismissed and disdained. God will end grumbling, sometimes punishing us even in His provision.