God is not progressive. He is the same yesterday, today and forever. The Lord decides what is sin and what is righteousness.
A real Christian, if he believed that Zimmerman had sinned, would have called him to confession and repentance. This would have shown true Christian love and forgiveness as there is no condemnation for those in Christ Jesus.
Instead, Wallis uses the jargon of phony "progressive" faith to beat Zimmerman rhetorically. This is truly a sin before God.
Wallis is acting like a Pharisee and should himself confess and repent.
Just like Jim Jones.