The zealots on both sides of this issue can argue from now until the Sun goes nova and they'll never find common ground.
It's because zealots are so self-rightous and convinced of their own correctness that they see no reason to bother to hear any descenting views. Which is why zealots of all kinds never solve, they only contribute to global problems.
However, it should be noted that the first amendment provides for freedom OF religion, not freedom FROM religion.
The purpose of the first was (right at the top) to state that they didn't want a specific state controlled or imposed religion like they had in England at the time. It wasn't intended to completely segregate all religious elements - that would have been antithetical to the founder's basic principles. It was strictly to avoid another Church of England and insure that churches of all kinds would be allowed.
"...We hold these things self-evident, that all men are created equal, that they are endowed by their Creator..." - seems doubtful that a phrase like "In God we Trust" or "one nation under God" would have bothered the founders.
The founders also clearly had no expectation of a complete elimination of religion from state operations - they've had a chaplain opening legislative sessions with a prayer since the Continental Congress in 1774. And there's been a Chaplain of the House and Chaplain of the Senate since the first congress in 1789.
Clearly their intent was NEVER to remove religion as a whole from government - simply to insure that a Church of America wouldn't one day be established and all other religions and churchs persecuted.
The vehement attempts by zealots to "protect" people FROM religion is just as absurd and dangerous as the zealots on the religious right trying to shove their specific religious interpretation down people's throat. Zealotry of all kinds is dangerous.
God's giving a tour of Heaven to a new arrival and after seeing the Jews, Muslims, Christians, Hindi, etc. are all happily living together they come to a wall. The new arrival asks what's behind the wall. God says "Oh, that's where the Catholics are - they like to think they're the only one's here 
- substitute the religion of choice.
On the flip-side, the founders would not have wanted something like a religion-specific prayer to be mandated in schools - e.g., even while the founders were themselves Christians, they would have objected to requiring the recitation of the Apostle's Creed in school for the simple reason that it would institutionalize a specific religious form.
An expectation of religious neutrality does not infer anti-religion.
