It sounds like you have bought into the fox news talking point that "marriage" is fundamentally a religious word and civil union is a legal thing. Merriam Webster's first definition talks about marriage as a union in law. It doesn't even mention religion at all in fact. Dictionay.com mentions both, though "legally" is mention before "religiously". The English word marriage, in the United States, can refer to either the government approved legal contract, or a religious ceremony. If we want to separate the church and state, let's invent a new word to refer to the religious aspects.