#korach accused Moses of the very thing that Korach was guilty of: self-aggrandizement. Projection is typical behavior of people who cry about fairness. Moses didn't promote himself, but #korah did. Numbers 16:3

Moses's first response to Korah's rebellion was to pray on their behalf. "Pray for those who persecute you." Numbers 16:4

God's anointing isn't subject to vote or argument. God chooses whom He will. Complaining that God's anointed is anointed is a complaint against God, not the man. Those who reject Moses aren't rejecting Moses at all. They're rejecting God's anointing, God's Law, God's sovereignty. Numbers 16:5,11