Is Freedom of Religion a Good Amendment?

Dawkins attacks the 'special respect' religion gets, making a nice point that, in America, cancer patients cannot smoke marijuana, but obscure religious sects can use hallucinogens. He points out that if aesthetes claim they need hallucinogens to appreciate art, they'd have no legal basis for this. He claims these situations are equivalent. But, in America, we legally acknowledge in the Constitution that these situations are not at all equivalent: religion is not the same as art; there is not freedom of artistic appreciation in the Bill of Rights.

The differing treatment of religion between Europe and America, I suspect, relates to our different histories. Europe suffered through centuries of religious violence and persecution, and as a result, they draw a circle of silence around religion: France will suppress religious expression; Italy has laws against defaming religion. Knowing firsthand the horrors of religious violence, they seem afraid of it. (I would argue that America has an analogous relationship with race - having suffered from centuries of racial oppression and violence, we are sensitive to the issue, in a way Europeans might not be.)

America, however, never suffered from large scale religious violence: in fact, America began, in part, as a solution to Europe's religious violence. I would argue that the Pilgrims' experiment was, by and large, successful - but, just as it is reasonable to question the relevance of the 2nd amendment today, it may be reasonable to question the relevance of the 1st. But the criteria for revoking or curtailing amendments ought to be pretty stiff.