Please show me where Scripture requires anyone to wear a certain kind of attire in order to worship God. Please remember that the old covenant is obsolete, as it has been replaced by a new covenant. So one cannot appeal to the Old Testament for any proof text for such a requirement. Not once did Jesus nor his apostles require or instruct believers to do such a thing.
I would urge letter writers to allow freedom in this area and not accuse a fellow Christian of disrespect, creating disunity within the Body of Christ.
The Lord looks at the heart of and individual, not the exterior. We know this because Scripture tells us. Jesus called the Pharisees hypocrites, who by outward appearances seemed righteous and pious. "Woe to you, teachers of the law and Pharisees, you hypocrites! You are like whitewashed tombs, which look beautiful on the outside but on the inside are full of dead men's bones and everything unclean." -- Matthew 23:27.
My advice would be to praise the fact that people are worshipping God and praising his Holy Name.
A letter writer said he put forth his best every Sunday, including his clothes. That is fine, but that is his choice. My best may not be good enough for some churches, but anybody is welcome at the Cowboy Church, because we want them to hear the Word of God.
MIKE WATSON, Jackson