The Founding Fathers had the (for them) relatively recent example of early 17th century Europe tearing itself apart as rival gangs of xtians slaughtered each other to show who had the better invisible friend.
In general they were deists - they didn't give a rats' ass about jesus - but they did understand that religious strife was not a good thing. Thus the freedom of religion is meant to prevent any sort of state sponsored religion which, in their experience, would inevitably lead to vicious xtian morons killiing everyone who disagreed with them.
Voltaire's comment 'I disagree with what you say, but I will defend to the death your right to say it.' was a guiding principle for them even if it is anathema to religious assholes.
In general they were deists - they didn't give a rats' ass about jesus - but they did understand that religious strife was not a good thing. Thus the freedom of religion is meant to prevent any sort of state sponsored religion which, in their experience, would inevitably lead to vicious xtian morons killiing everyone who disagreed with them.
Voltaire's comment 'I disagree with what you say, but I will defend to the death your right to say it.' was a guiding principle for them even if it is anathema to religious assholes.