The procreation argument in particular is a nonsense. Lots of infertile couples marry, and lots of married people also choose not to have children.
As for the rest of it, Henry VIII made a very public mockery of the Christian concept of marriage hundreds of years ago. People got over it eventually.
The new law doesn't force any religious bodies to marry gay people. They can feel as upset as they want about it, it is a free country we live in, but our elected Parliament has voted overwhelmingly and across party divides to change the law on this matter and they'll just have to learn to live with that. This is not a theocracy.
On procreation, gay people are not biologically capable of procreating with their partner. That isn't a moral judgement; it is a simple biological fact. Choice and fertility are irrelevant as even if both gay partners are fertile and want children, they still cannot procreate with each other. They need a third person.
Men and women have been making a mockery of marriage throughout its history so I am not sure what your point was? Do you think Henry VIII was the first man in history to murder his wife or change a situation to suit himself?
We are not a theocracy and I am glad about that. Indeed, those who disagree with gay marriage for whatever reason will have to live with it. That is the burden of living within a liberal democracy - all of us have to live with something we don't like. Including you, because you don't appear to like religion very much! However, on the point about not forcing religious bodies to enact gay marriage, I doubt very much that would stand a legal test but I am sure we will find out soon enough.