Told myself I would not get involved in what inevitably turns into mud-slinging. Oh well!
First, the debate will always be frivolous if each opponent takes as a starting point opposite foundations. This current debate is merely the symptom of much deeper and much more serious ones – like our place in the world, purpose and meaning of life, moral truth etc. And then there are the two different questions: the moral question and that of legality, and legislation in light of morality etc.
In terms of equality of rights, such is simply achieved by all peoples being afforded the same abilities and functions under law. Now, so far as I know, civil unions grant the same functions (rights) under law as marriage does. This being the case – equality already exists in this respect. The Civil Union Act grants rights the Marriage Act does. Obviously, then, there is a social motivation to it all. Some don’t merely want a legally recognized union. They further want to disregard an established force which has clearly and successfully served the world, and essentially change it, and by implication, whether implicit or explicitly stated, indicting its entire history to this point. Whatever one’s reasoning behind pursuing such a course of action or cause, it does lead me to wonder to what extent changing such foundational practice (as marriage) changes society and culture at large in the long run – beyond the merely superficial aspects one might raise.
As they say, ideas have consequences, and we are largely the product of our environment. So let's not act as though this issue is exempt from this.
Someone here said that it is “all subjective”. This is very sloppily phrased. Does everyone have their subjective opinion? Sure. But does that mean there is no objectively true right and wrong, good and bad? Hardly. People can have their subjective views – but they can be wrong! (if there are moral facts that are beyond merely subjective). And merely citing that people have different views in no way entails there is no correct view.
Now to some the question of SSM is not a moral one but a legal one. To some it is a moral one. To some it is both. And some wish to eschew the democratic process by making vacuous appeals to emotion using watchwords and phrases (e.g. ‘love is love’) which they would never wish to use to defend other new pushes and movements which are currently emerging (that would make most sick to their stomach). Some think legislation should be based on what is morally right. But not everyone agrees with what is morally right or whether this is a moral issue. And so on.
In the end, much of the debate stems from another debate: regarding the ultimate nature of reality and whether or not we exist with any purpose above the purpose one gives to themselves. And really, if everything (morally) is subjective, and if there is no real purpose to our lives or ultimate significance or reason why we exist…then there isn’t much to say – no one would hold valid grounds to indict and moralize against anyone.
Ultimately, as I said at the outset – if opponents begin with different assumptions and pictures of the world, the debate is frivolous.
And also, regardless of one's position here, those who so cavalierly say “In couldn’t care less what two consenting adults do” – yes, you do. Maybe not as regards the current topic at hand, but certainly for other topics. But I won’t cite examples, at risk of erroneously being accused of equating things.