Whatever happened to the Tory party of the 1980s that refused to use taxpayers' money to prop up failing industries making things people didn't want? That told us sternly, usually in a helmet of hair-lacquer, "the market must decide"? It turns out the Tories aren't so laissez-faire if the market makes a decision they don't approve of – particularly when punters turn their backs on one of their most cherished institutions. With fewer people getting married now than at any time since records began in 1862, the Tories – who despite what they say about free markets, always know best how people should live their lives – have decided to effectively take this failed enterprise into public ownership.

This weekend a former Tory MP from the 1980s, who considers himself culturally progressive, came out in support of David Cameron's promised tax breaks for married couples. "From this day forward, reward married couples" announced Matthew Parris in the Times. He failed, however, to explain why married couples should be "rewarded" – as well as given wedding presents. But then so has DavidCameron.

But the article's standfirst succinctly summarised both Parris' and the Tory position, and made it clear why an explanation isn't necessary: "Everyone except a sour minority knows that marriage is good for society". Marriage is good for society because it is a "good thing" in and of itself – as such it doesn't need to be demonstrated, even at a time when marriage is less popular than ever. Marriage is, for most Tories, an article of faith.And anyone who disagrees with this position or even questions it is obviously sour or leftwing, which amounts to much the same thing.

What made Parris' support of this tax on unmarried people (for that is of course what it translates into) novel was his interesting claim to speak on behalf of the vast majority of gay people: "an astonishingly conservative section of society", commending their "traditionalism", warning the (presumed heterosexual and conservative) reader who begs to differ they've been paying too much attention to a "sour slim minority", and asserting gays' overwhelming endorsement of the proposed subsidy for married couples. Parris even went a step further than Cameron and called for civil partnerships to be excluded from the "reward" – perhaps because being famously gay himself, Parris can't be easily accused of homophobia.

Now, maybe I'm just a sour lefty minority homo of exactly the kind that Parris warns you against, but at least I know better than to presume to speak on gay men's behalf – especially when it comes to counting yourself out of tax breaks. But since Parris has raised the matter of sexuality, I feel obliged, like the bad fairy at the wedding, to point out where this policy is coming from: essentially the same bit of the Nasty Party that brought you Section 28 in the 1980s, with its jihad on "pretended family relationships", though it is now more closeted.

Section 28, you may remember, is the same anti-gay law that the main champion of the Tory marriage subsidy, the Catholic convert Iain Duncan Smith, wanted to reinstate in 2002 when he was Tory leader. This piece of legislation grew directly out of Tory and tabloid fears that marriage was being undermined by acceptance of homosexuality. Section 28 was essentially a nannyish backlash against the scandalous notion that schools might tell young people they have choices about who and how they were going to love.

Now that "pretended family relationships" – straight and gay and everything in between – are probably in the majority and Section 28 is a discredited, embarrassing memory, Holy Family Tories such as IDS have to adopt a different, "nicer" approach – one that seems more carrot than stick, more utilitarian and less homophobic. But don't doubt for a minute that one of the biggest attractions of what we should probably call "Section 29" for the IDS tendency is that tax breaks for married/decent people is a satisfying way of sticking it to unmarried/indecent people.

Tories, particular the older ones who make up the majority of the party's aging membership and who give IDS his power base, have never really reconciled themselves to the massive cultural changes that happened post-1960s – and which were much accelerated by their market and consumer reforms in the 1980s. For all her "Victorian values", Broken Britain was broken in large part by Thatcher. I doubt that Cameron believes for a minute that his Terry and June subsidy will turn back the clock and make marriage or Austin Allegros fashionable again, and he probably doesn't really want to anyway, but it's nice that he's figured out a way to buy off the IDS tendency that so distrusts him and what they see as his cultural liberalism – with taxpayers' money.

I can't help but feel a little sorry for Parris though. It can't have been easy being a gay Tory MP in the 1980s – at least if you had, as I'm sure he has, a conscience. But it seems that all his futile attempts to convince his Cro-Magnon colleagues back then that most gays are natural Tories and worshippers of the Holy Family despite their penchant for buggery has taken its toll. He now believes his own rhetoric.