I don't know what the situation is in the US; in the UK, all schools include RE (religious education) which covers an introduction to the major religions of the world and their associated scriptures, with particular emphasis on Western Christianity. This is considered (and I happen to agree) a valuable prerequisite to the study of history and literature as well as a contribution to individual spiritual growth
Nothing wrong with that. Most of the evolution supporters would probably agree. The conflict arises when folks want their literal interpretations of Genesis to supersede what's taught in science class. Science classes shouldn't be perverted by theology, and of course, vice versa.
in the UK, all schools include RE (religious education) which covers an introductian introduction to the major religions of the world and their associated scriptures, with particular emphasis on Western Christianity.
I don't think it is unconstitutional in the US to teach such a class in public schools, provided it isn't biased towards a particular religion and provided it doesn't advocate religion in general. It would be okay to teach the history of religion as a history class. However, that's not what the religious fundamentalists want.
The enemies of the Theory of Evolution really don't want Evolution taught at all, and they want to proselytize their own version of Christianity in public schools. They also want science subservient to religion.