People who quit the Church because of the bad behaviour or attitudes of others always struck me as a little Pharasaical.
I'm not talking about people who quit for serious differences on the issue of belief. It's only normal that you want to change church when you don't share the creed of the one you're in.
I'm talking about people who think that the other members of their church are too sinful or morally compromised.
Christ came to reach sinners after all.
"I like your Christ, I do not like your Christians. Your Christians are so unlike your Christ."
You see a lot of fat, unhealthy people at the gym, too. Does that mean you shouldn't join the gym?
Besides, their interpretation of what Christ was all about is often based on the zeitgeist of the day than the actually text of the Gospel.