Matt is NEVER evenhanded. When the falsely accused killer knew he was innocent why would he stay and face "justice" in 19th century Kansas. Not sure what episode, but Matt took an innocent man to hang and he knew it! Matt gave him chances to escape but the "criminal" was too honest to try. Matt should have arrested him in the first place.
In another a convicted murderer escaped and Matt was sure he was innocent. Another prisoner killed the guard but he was charged with murdering the guard. He had a wife and newborn baby but Matt and Chester still go after him. Even when they find out that it wasn't this man that killed the guard they didn't give up. He left with his wife and baby and Chester was the one who found them and Chester was the one that had a heart. When Matt showed up he did end up agreeing with Chester as the couple rode away, but it just seems to me that Matt is VERY inconsistent. He always talks about "the Law", but he never thinks about justice.