Minor correction--It's not SUPPOSED to be for entertainment. Nor is it supposed to be for arbitrary judging or social snobbery. Yet for many churches that's what it is, especially old-school churches. I grew up in an Assembly of God church, and while they were actually pretty good about not calling out groups of people for Hell and damnation (I do think I heard Mormons mentioned once), there was definitely a vibe of what was acceptable dress, behavior, etc.
My mother told me a story once of a church she went to as a young woman. One Sunday morning a homeless man came in for a service and was promptly shown the door. He was quiet and respectful, but he was not welcome because he was indigent. The very kind of person that Jesus would have sought out and brought in was rejected, because he wasn't dressed properly.
The church that I (infrequently) attend now is very casual about dress, and very accepting of pretty much everyone. People attend in shorts and flip-flops. I can't make myself do that even to this day, but I'm glad that people have the option. My only quibble is that they do lean a little heavy on the entertainment side. I've never liked Christian music.
This is because ALL Churches are made up of sinners. The Church I have been a member of for over 20 years drives me crazy sometimes. Some churches may indeed think they are perfect, which is exactly one of the symptoms of utter failure on the Churches part. The only PERFECT thing we have in the true Church is a perfect savior in Jesus Christ and The perfect Word of God, the Bible. Each man must work out his "OWN salvation in fear and trembling."
To the church of the Laodiceans:
 Because thou sayest, I am rich, and increased with goods, and have need of nothing; and knowest not that thou art wretched, and miserable, and poor, and blind, and naked: