you're making a lot of assumptions
here about who I am :-), I'm afraid; those may not necessarily be justified. One of my first forays here was a discussion about a universal health service (it's scrolled back, I'm sure, by now; a page or two.)
I'm sure you're right about religious conservatives, but first, if their ministers told them it's no big deal, they would probably not worry as much; and second: their worries can be addressed on the state level. There's no need for amending the constitution.
I don't know what the difference between "marriage" and "civil union" is.
At any rate, this should't be such a big issue. So long as it doesn't affect me in any way, I don't see why I should worry about gay marriage. Surely a lack of health insurance will affect any marriage more than any gay this and gay that bs.