Man, who made Me a judge or an arbitrator over you?
Human history shows us that mankind has consistently used God for its own end. We are free to speak our minds because our Creator gave each of us a free will. This is why some see themselves as spokespeople for God. They don't necessarily love His Word or have a fear of Him in their hearts, but they speak anyway . . . from their darkened imagination.
It's common for political and religious protesters to hold signs with Bible verses on them, completely out of context, to try and justify their cause. Politicians will often quote a Bible verse and make references to God to get votes. Nations go to war and say, "God be with us," as did the Nazis or other harmful people groups. Religious leaders will post and go live bashing people or hold signs protesting on things because they're legalistic. They have no true understanding of God's Word and use it way out of context. They are no better than the politicians.
In this verse, someone in the crowd wanted Jesus to side with him in his cause, but Jesus would have none of it. If we fear God we should never use His Word to justify our actions. Rather, we will always be guided to His will BY His Word.