as we have seen with the second amendment, the bill of rights can be "interpreted." so we might assume, unless we are as simpleminded as you are or are pretending to be, that freedom of religion would stop somewhere short of, say, human sacrifice.
a religion that seeks to overthrow the tenets of our constitution, as islam clearly does, would not enjoy unlimited protection and, if its preachings required such a belief, any protection at all.
dep