The simple solution would be for the city to adhere to Article II, Section 4 of the Colorado Constitution, to wit:
No person shall be required to attend or support any ministry or place of worship, religious sect or denomination against his consent. Nor shall any preference be given by law to any religious denomination or mode of worship.
Clearly he misspoke, you keep opinions like that to yourself. My impression, other posters who aside, is that Denver has an active athiest community. They'll make use of that.