I can remember telling my RE teacher that I didn't think RE should be taught in schools. (This was at secondary school, and I dropped R.E. before O-level so I think it was some kind of general studies lesson. ).
However, now I am older and wiser I have completely changed my mind. People need to know about the history of belief and the differences between catholics and protestants and muslims and jews, now more than ever.
Also, the difference between Abrahamic religions and traditional chinese belief systems.
You could do all of this in history/geography/sociology, but its such a big topic that why wouldn't you have a whole subject called R.E?
God forbid that it should ever be taught as science...