RE is what is known as base curriculum and is the only subject taught by law in the UK under the provisions of the 1948 and 1988 Education Acts. Schools have a statutory duty to teach RE. As it is compulsory at KS4, it is thought worth the students getting a half or whole GCSE in it.
The whole point of being an RE teacher (and I am one), is that we TEACH, we don't preach. I believe that the best RE teachers don't have a religious belief and are either atheist or agnostic.
My aim in life is to ensure that students have a degree of religious literacy when they leave school. I don't give a flying fuck whether they believe in God or not, if they are a Jedi, and atheist or worship a sky blue pink flying spaghetti monster...what I do care about is that they have enough knowledge about the nuts and bolts of religions and what impact this has on their lives through things such as abortion, euthanasia, changes in the law to allow civil partnerships, religious tolerance, how not to get yourself knifed, and why you don't offer your Muslim or Jewish mates a bacon sarnie, to get by when they leave school.
Many students don't live in multi cultural areas, and so this is very important for them when they leave home and go to uni.
Why don't you guys find out what exam board your kids are doing and then look up the syllabus. Edexcel for example covers abortion, euthanasia, contraception, homosexuality, civil partnerships, community cohesion (racism, discrimination, prejudice, benefits of a multi faith society, benefits of a multi ethnic society, problem of evil, for and against the design argument) and that's the short course.
The other paper covers just war, cloning, genetic engineeering, IVF, transplants, environmental issues, hunting, animal rights, situation ethics, how we are governed, attitudes to punishment. It looks at the secular response to these things and the law, and then examines what two religions think about these things, and what different branches of these religions think. It's an academic subject, no more, no less and is interesting and informative. I wish I'd done it instead of bloody chemistry, I might have got another O level instead of an ungraded.