it's like free speech.
because Larry Flint can publish whatever he wants, because the KKK can say whatever they want, i am free to say whatever i want. (beyond the obvious "fire in a crowded theater" distinctions).
it's also like the separation of church and state. it is precisely this separation and the existence of a secular government that allows everyone to practice their religion as boldly and as robustly as they see fit. if the state were to endorse a particular religion -- and, yes, even religion itself -- *that's* when you'd start to see the rolling back of all the religious freedoms you now enjoy.