The confusion comes from not differentiating between marriage, a union based on pledged love and personal commitment before God, and thus a religious event - and civil union, a government status that enables shared administrative representation.
Separate the two and it all becomes clear. Marriage should not be reachable by the government because its love and religious qualities are outside the evaluative powers of government by definition.
Marriage should also not be termed alone, but in reference to the spiritual tradition, religion or church from which it is derived in each case. This is true anyway - religions don’t generally accept marriages outside of their own tradition.
Then, as a separate event, people should have to file a separate petition for civil union with the government that is - never - called “marriage.” And to prove it, marriage should not be a prerequisite for civil union. The government deals in contacts, so a civil union is a contract between two (or more) people and the government - but it is not a marriage.
The bottom line is that if you think the government solemnizes marriage, then you equate government with God - and that is the definition of communism.
Linking marriage only with its religious source is the solution to this dilemma. If your religion doesn’t perform gay marriage, then it should be irrelevant to you if some other religion does. And if government gets out of the marriage business and only administrates civil unions, then it has no way to have any effect on anyone’s marriage.
Problem solved.
Civil unions do not solve the problem. In a free society I should not be forced to recognize or give benefits to any non-marital union. Furthermore, I should be able to recognize and freely give benefits to marriage that are not open to others. Nor should the state recognize these unnatural unions and give them the sanction of society.