Well no, it was not driven from the law side here. It was driven from the vice side. They covet the fame, the name, and then not even (mostly) to use them, but just that they sit there as a symbol.
Here’s a portion of Wikipedia’s entry for “civil union”
Many supporters of same-sex marriage state that the word ‘marriage’ matters and that the term ‘civil union’ (and its equivalents) do not convey the emotional meaning or bring the respect that comes with marriage. Former US Solicitor General and attorney in the Perry v. Schwarzenegger case Theodore Olsen said that recognising same-sex couples under the term ‘domestic partnership’ stigmatizes gay people’s relationships treating them as if they were “something akin to a commercial venture, not a loving union”.
So thinking back to an earlier post, yes, the controversy is about a “word”. Gay couples, so that they can command more respect, want to be called “married”.
My God, is the Supreme Court supposed to rule on the question of what a pair of gays is called?