A reader makes an entirely fair point:

Dear Jonah,
Civil unions would be a good deal easier for some of us to swallow if the status were available to any unmarried pair of human beings who choose it for any reason, such as a middle-aged single woman and her elderly dependent aunt. If gays want the practical benefits of such a union, fine, but I don’t see why homosexuality should give them priority over other people with no sexual link who also want the benefits of a unique non-marital partnership. In other words, I’m willing to consider not discriminating against homosexuals, but I’ll be damned if I’ll discriminate in favor of them.
Best regards,
Name withheld