One is religious, and I doubt you’d sympathise with that; let’s just say an easy way out of that one would be to defining all civil unions as such, but it actually would miss some point.
Another one is biologic: heterosexual couples are expected to have children. Of course, that should mean that couples without shouldn’t benefit, but they might be considered saving money while planning, and there is the embarrassing debate about what to do with people marrying in their 40s… That goes against the increasingly visible case of gay couples adopting, or using donations/surrogates. But the idea is: that tax benefit and public recognition is a natalist argument.
And the important point here isn't the validity of these arguments, it's that people do use them to inform their position on gay marriage, and that that is orthogonal to being "anti-gay".
I’ll jump on my militant stead now, and attack you bitterly on one of the things I actually care deeply about: the abuse of the idea of ‘perpendicular’ in non-obvious algebraic context.
(I’m like that: you can way what you want is subjective, but Statistical methodology… I instantly switch to heavy weaponry and my loud voice.)
If you mean conceptually independant: absolutely. Social recognition of a homosexual orientation has been associated with many choice patterns, most of which didn’t include marriage, mainly because that hasn’t been a historically considered model: priesthood, separation of family ties and sexual pleasures, even projection onto educational purposes…
If you mean “statistically not correlated”, then you are wrong: there is a high correlation between people holding unambiguously homophobic position, and them opposing same-sex marriage.
You can’t consider one in abstract without the other.
Let’s take an example: There is little logical connection between being rich and behaving like a jerk, yet… psychological experiments tend to indicate the former appears to cause the later. If you want a more honest society and a fair market, that correlation needs to be considered to inform reforms. There is little formal connexion between coding and favoring libertarian ideas, yet… that happens a lot, and it does influence the role of technology in society. If you held sincerely an opinion that is mainly shared by jerks, that’s fine if you are not one -- but you can’t expect to defend it without some preliminaries; not excuses, just precautions.
It doesn’t, but it appropriates an institution meant to protect childbirth for a different purpose. It denatures something seen as precious.
That can seem meaningless to a liberal, but conservatives have a heighten sense of ‘purity’, and tend to vehemently refuse misappropriations or risk of ‘contamination’, sometimes beyond the scale of the real issue. Examples in the US include: ‘sacred’ money meant for church should not be taxed by secular government, or, benefits meant for people in need should not go to undeserving people; one should not indulge people who commit crimes; young impressionable teens should not frequent lost souls, etc.
And to be clear: yes, that should mean people shouldn’t marry after menopause -- rationalisation of that include continuity, traditions or even direct reference to Abraham and Sarah. Details are probably more individual.
What matters is that you understand there is a consistency to the over-all idea, in spite of the apparent contradictions, and you can’t move forward unless you make sense of it. It‘s the classic exercice in rhetoric of being able to convincingly prove the opposite of your position in order to be able to defend it.
One is religious, and I doubt you’d sympathise with that; let’s just say an easy way out of that one would be to defining all civil unions as such, but it actually would miss some point.
Another one is biologic: heterosexual couples are expected to have children. Of course, that should mean that couples without shouldn’t benefit, but they might be considered saving money while planning, and there is the embarrassing debate about what to do with people marrying in their 40s… That goes against the increasingly visible case of gay couples adopting, or using donations/surrogates. But the idea is: that tax benefit and public recognition is a natalist argument.