The psalmist ask this question because he is awe-struck at the incredulity of these people who raise themselves up against the Lord of glory. He doesn't refer to one person but a nation of protesters. Is it possible that so many people could try to find fault against God? Yet, many people think that if there are enough people who turn against God, then God will change, but that is a fantasy. See how many have turned against God since the beginning of human history, even since the coming of Jesus Christ in the flesh. Has God changed? No See how many have left the Church and started so many denominations, causing disunity in the One Church of God. Has God changed? No Why do they protest? They protest because they do not have the faith to see that God is Love and that unless he were love, neither could they protest nor exist. By their existence he shows his power, by allowing them to protest he shows his mercy and patience.