David was not calm when he wrote this. The surrounding verses describe cords of death and torrents of destruction. What separates David from the remnant in Malachi is not the intensity of his distress. It is the direction of it. David cried to God. The people in Malachi talked to each other.
That distinction is not a small one, because Deuteronomy 6:5-7 had already told them what to do with their words. Love the LORD your God with all your heart and soul and might, and let these words be on your heart, and talk of them when you sit in your house and walk by the way and lie down and rise. The remnant was doing exactly that. Sitting, walking, lying down, rising, and talking. They had simply changed the content. Instead of discipling one another in the faithfulness of God, they were discipling one another in cynicism, and their children were listening.
This is why complaining feels so much like community. It gathers people. It creates agreement. It produces the warm sensation of being understood. But it manufactures no faith in anyone who hears it, and it slowly forms a whole household, a whole small group, a whole church, into people who assume God is absent. Lament has a direction; it goes up. Cynicism has an audience; it goes sideways.
The remarkable thing is that God was never unwilling to hear it. From his temple he heard David’s voice. The complaint was welcome. It was just never brought.