Does the church show favoritism? You bet. Probably much to God's dismay. Favoritism was condemned by God in the Hebrew scriptures, Christ and the apostles in the Greek scriptures.
The church will allow certain sinners to remain involved, serve and even lead. All of these behaviors have been condemned in the scriptures such that people who repeatedly commit them should be expelled...if not stoned, but not in the church: adultery, divorce, greed, jealousy, envy, selfish ambition, pride, outbursts of anger, tattoos, shaven faces, thievery, cheating, lying...The list goes on to include idolatry which is worshiping other things as gods, like money, sex, entertainment, success, power, family, romance, nationalism, and anything else which we think will fill our spiritual void. Children, young and old, who dishonor their parents or are stubborn and rebellious should be stoned according to some verses. Irritability can be included as it's based on selfishness--the god of me--as well as favoritism.
But the church doesn't talk about these sins publicly, picket against or take out ads opposing these sinners' rights or prevent them from being leaders in the church. These sins are sometimes hidden, sometimes public but hardly ever are people who practice them held accountable in terms of participating in the church.
But if a person practices love, joy, peace, patience, kindness, gentleness, goodness and self-control, they should be a part of the spiritual community of believers. Paul says, "against such there is no law." Even though we are worthy of being condemned for we have dishonored our Father in heaven, been rebellious and stubborn, instead of stoning us, He races out to meet our humble selves and welcome us back into His family. This is mercy. This is grace.
