I have no interest in whether or not Britain is a 'post-Christian' society (whatever that might mean)
Gordon explained it extremely well in #47.
nor am I worried about what the UK civil law has said.
Unless you're a master criminal I'm pretty sure you're "worried" about what the law says in every other regard. A law regarding marriage between two people of the same sex is presumably one unlikely to be of use or interest to you in any case, so as was often said during the equal marriage "debate", there's no need to concern yourself with something that doesn't apply to you and never will.
We all know that legislation can be wrong or poorly created, and can fall over a period of time.
Not this one. As I've said before, the arc of history runs one way only on things such as this. Across the twentieth century the trend in all civilised places has been toward greater personal freedom and the emphasis on the rights of the individual. Votes for women, emancipation of women generally, decriminalisation of homosexuality, equal marriage, legal sanctions against discrimination on all manner of grounds (race/ethnicity, age, sex, physical ability, etc.), reproductive freedom ... it's a long list. Not only are these measures not repealed, they're consistently extended (albeit far too slowly) because all rational people of goodwill recognise that they're good for individuals and good for society as a whole. Removing backward and ignorant forms of discrimination, discrimination based on noxious, ugly, divisive and illiberal attitudes, makes individual people happier and society better for it.
I believe that this is a flawed piece of legislation, whether it exists in the UK, the USA or anywhere else in the world.
Nothing flawed about it - with regard to England and Wales it went through the proper channels exactly the same as any, in fact
every other piece of legislation. Equal marriage in Ireland couldn't become law without majority approval for a change in the Irish constitution; a vote was held and a majority wanted to see such a change, so equal marriage become law. Simples. It's a progressive move that benefits a particular sector of society - or societies, rather, since more and more countries are legislating for equal marriage. Finland's bill has been passed and comes into force in just over a year's time, on March 1st 2017. I gather that Australia, Chile and Switzerland seem likely to be next on the list.
As for whether or not one is married, traditionally marriage was in the eyes of God - not civil law - as there were no civil benefits attached to being married until 100/150 years ago.
Yup. The Marriage Act 1836, to be precise. (Opposed by the C of E, needless to say). Glad to see you're finally catching up with the nineteenth century.
