“ I can’t really be married to a same sex person, for the same reason that I can’t flap my arms and fly.”
Your arms don’t have the structures necessary to lift an object of your weight. Biology and physics.
Marriage is a legal partnership with very specific limitations and privileges. Law, not biology nor physics.
“Nature makes some things have certain functions, and calls them birds.”
Nature made the functions. Humans determine the definition of birds (some of which cannot fly), and bats (which can fly but are not birds).
You oversimplify and make it erroneous.
“They are different than humans. No amount of saying you are a bird will make you one.”
Same goes for bats, though.
“Nature makes male and female animals function in certain ways. Those ways don’t work right unless one animal is female and one is male.”
Which has nothing to do with the legal definition of marriage. Male and female dogs cannot marry because they cannot consent to contracts.
“No amount of saying that 2 animals of the same gender are the same as a male and female pair will make it so, even if the government says it is so. Governments can’t make 2 + 2 = 5 by saying so.”
No, but governments CAN extend legal status to whoever the fuck they want to.
“B). It is not about a religious belief.”
It’s very much about the religious belief. There is no secular reason to think that marriage is entrenched in biology.
“It is a fact of life like the birds and the bees. That’s just the way it works. Make up a new name for your clearly different thing, and we can all get along.”
Nope. There are a couple hundred uses of ‘marriage’ that would not necessarily extend to any civil union or secular partnership or whatever.
Each and every business or agency (hospital, insurance, prison, school) which recognizes privileges for one’s ‘married spouse’ would have to be taken to court to prove that alternate partnerships counted the same as marriage.
Far easier to just grant them marriage, to give them the same rights, privileges, access, which is what they demand, and why.