"Idiotic religious reasons"

Why is it when a person chooses to not do something they use an argument like "they only started that for idiotic religious reasons"? Any other time that person would tell you that they pray before each meal because they are a religious family that has had this tradition for as long as they remember. Or they don't eat meat on Friday because that's what their faith believes in. Or they go to Midnight Mass on Christmas Eve because it is their religions belief that their Saviour was born that day. Funny how people will use religion as an excuse for anything no matter if they want to continue doing it or not.