Sometimes we forget that not all relations, not all behaviour in the past, were controlled and restrained by law, or needed to be. When vulnerable behaviour is protected by law, the role of personal decency starts to seem disposable. You've got the laws you asked for – why do you want people to be nice as well? Or, even worse – we're being nice to you because the law tells us to be. That's good enough, isn't it?

This may be the issue with the acceptability, or otherwise, of gay people in society. The legal protections are all pretty much in place, and the principle of equality enshrined. When same-sex marriages start taking place next March, we can work wherever we choose; hoteliers may not turn us away; we must be treated equally by the providers of goods and services. We must not be abused in the street on the grounds of our sexuality. You must be nice to us. It's the law.

The grounds are set for a small but emphatic backlash. It's easy to point to international examples, where individual jurisdictions have decided they want nothing to do with the general spread of liberalising legislation, and are going to make a stand. India's supreme court overturned a 2009 ruling decriminalising homosexuality, arguing that it was not an equality issue. An Australian court disallowed gay marriages, which had already taken place in the Australian Capital Territory. A referendum on gay marriage in Croatia produced a firm rejection. A ruling by the European court of human rights about gay marriage was rejected by Greece. Russia is enshrining prejudice and creating opportunities for physical violence against gay people through its laws. And so on.

It is easy to say that things are much easier in the UK, and the legal protections are now firmly in place. But the difference between anti-discrimination laws and a change in culture can make things less clear. A generation ago, people bemoaned the alteration in the meaning of the word "gay". Now, very similar people are discovering the virtues of semantic change and are firmly defending a shift in the sense of the word to mean "rubbish", in the face of a school playground campaign by Stonewall. When the diver Tom Daley came out, he hardly had a word to use of himself, as hundreds of other young gay people must be finding.

And the reaction to Daley's coming out showed an interesting cultural problem, not to be legislated against. There was a largely positive response; and there was also a banal online flurry of old-fashioned abuse. More interesting, however, was a widespread response that ran "Who cares? Why is this even news? Why are we hearing about this?"

For a standard response to shift from "We really don't want to hear about your disgusting private life" to "I'm too cool to want to hear about you being gay" is not much of an advance. At the last Olympics, 12,000 athletes included exactly three gay men who were out. Of course, Daley coming out was important news, for him and for the primitive culture of professional sport. To say "Why is this on the news?" is to demand silence from a minority.

Every gay person has examples of cultural contempt that no legal recourse can touch. Most people are reluctant to bring them up for fear of sounding petty. When I worked at the University of Exeter, every colleague who embarked on any step in the great journey of heterosexuality had it promptly marked with a general email from the administration about babies, engagements, weddings and so on. After my civil partnership, I had to ask a junior colleague to send a note round, and forever afterwards one administrator used to say "Your partner – oh, you like to call him 'your husband', don't you?" with a poisonous smile, as if it were a harmless eccentricity of my own that she might as well indulge.

Even to mention it seems petty; no legal sanction will touch, or ought to touch it. There's no law on earth to compel work colleagues to invite their gay team member out for a drink on Friday night, or to congratulate them on their marriage without making quotation marks in the air. Probably a generation or more will pass before such dismissive stereotypes stop being used in the most unlikely circumstances – once, I was discussing the marking of an MA thesis with a colleague at Exeter when another sailed past saying: "I can't think what you two queens are bitching about."

It's all on the way out: we are less likely to be beaten up than we would have been a generation ago, or if we were living in Russia. We probably have to resign ourselves to a generation of disadvantage – and the occasional, curious resurfacing of what never went away – while minds slowly change.