Some Christians are nitpickers. They constantly criticize others for such non-essentials as grammar, tattoos, piercings, hair color, musical taste and endless other choices which are often not even sin. As a result, such people are turned away from the church, rather than attracted to it. The Pharisees in Jesus' day were nit-picky about their religion too, but he condemned them for it. He expects Christians to act better than nitpickers. In Matthew 5:48 Jesus taught the disciples to become perfect and many understand that to be even fussier than the tradition-burdened Pharisees, but that would be wrong.
Being overly concerned with non-essential details is not what Jesus wants at all. The word often rendered as perfect is better understood to mean mature or complete. It has nothing to do with nit-picky religiosity at all. Being obsessed with non-essentials is in reality a mark of spiritual immaturity. Mature Christians are the salt of the earth. They taste good. Mature Christians are a bright shining light. They are liberated from nit-picky legalism. Mature Christians reconcile rather than harbor grudges. They preserve the sanctity of marriage. They are not pretentious, create good will and take insults without retribution. They are a very generous people rather than quibbling and would treat an enemy the same as a friend.