Some say the defining characteristic of Christians is a cross. Others say it is a certain style of worship music. Some say it is a denominational name.
What did Jesus say?
"By this all people will know that you are my disciples, if you have love for one another." (John 13:35, ESV)
The badge, the identifying characteristic, the mark of Christians is not a cross on a steeple, it is not a specific denominational name, nor is it a certain style of worship music or attire.
The defining characteristic of what it means to be a Christian, a genuine follower of Jesus, is love. We are to be known for our love of God that is expressed in love for one another. All people will know that we are truly living for Jesus when we are loving like Jesus.
So let's stop arguing about these other issues where good people can disagree, and let's love like Jesus!