The murder of Jody Dobrowski on Clapham Common at the weekend is an unusually shocking one, even for those who could have predicted it. Everyone gay has a story or an experience of abuse. Perhaps it is a matter of being shouted at in the street - an unpleasant experience if, as in my case, it happens to be the street where you live, and the one doing the shouting a neighbour of yours.

It might easily be a physical attack as you leave a gay bar, something much more common than most people believe. Gay bars now don't disguise themselves, and few of their patrons conduct themselves with any of that former shame which formerly made them, effectively, invisible to the wider community. Everyone has a story of an acquaintance followed, on leaving a bar, and beaten up.

Or it might even be within a gay establishment itself. The internet has been busy for weeks now with the story of a gay clubber at an after-hours club in Vauxhall who was violently kicked and punched by a straight gang. When the reputation of gay clubs and bars, with their conspicuous hedonism and grown-up bohemian cool, spreads beyond the community, they can start to attract people who may not be very enthusiastic about the specific lifestyle, and tensions grow to boiling point.

In a small way, I've experienced this. Everyone knows that there are some Soho gay bars best avoided at the weekend, which make a faintly hypocritical living out of entertaining hen parties. Once, on a Saturday night, my boyfriend and I were having a last drink after the theatre and dinner in a bar like this. A very drunk girl, her head wreathed in tinsel, wandered over and abruptly groped my boyfriend. She was told, pretty firmly, to stop and go away. She came back five minutes later, and, more aggressively, groped me. I removed her hand, and raised my voice. What came back was a real torrent of anti-gay abuse, all pretence of having a fun night out in the fabulous gay bars disappeared.

Of course, she attracted some hostile attention very quickly, and was removed. But what remained from that small incident is the impression that many people hold so low an impression of gay people that they believe it impossible that they would complain about a sexual assault. From that it seems likely that more extreme people consider that it hardly counts if you shout abuse at gay people; an attack on one isn't an important crime; even, perhaps, that what happened to Jody Dobrowski doesn't really count as murder.

Disgusting and shocking as this murder is, I do wonder whether we might, as gay people, start to reconsider regular patterns of gay behaviour. I don't say in any way that Dobrowski bore any responsibility for his own death. But what would be highly inappropriate, in the wake of this murder, is any insistence that gay men have a kind of right to have sex in so public a place as Clapham Common.

The existence of "cruising grounds", like the practice of having sex in public lavatories, is a strange remnant of a more difficult age. Perhaps 40 years ago, when it was difficult for gay men to meet each other and they were less likely to have anywhere to meet in private, there was some necessity for them. But these days, in London, there must be well over a hundred gay bars and clubs where it is not hard to meet a stranger and go home with him. A lot of bolder clubs and saunas advertise in the gay press as places you can actually have sex on the premises, and the police, considering them private places where anyone who has entered is unlikely to be shocked, turn a blind eye. And, of course, there is the internet.

To someone like me, who has lived a blamelessly monogamous life, even these enterprises seem more adventurous than strictly necessary, not, as Mrs Patrick Campbell would have said, being tempted by hurly-burly away from the deep marital peace of the double bed. But anyone who enjoys such things is welcome to them; if you don't like the idea of them, you don't even have to know about them.

But group sex on Clapham Common, or in a public toilet, falls into rather a different category. Anyone who responds to these things with violence or murder is clearly mad. But surely we can admit that they cause significant annoyance, at the very least, to the wider community, and not unreasonable annoyance, either. Once, taking a short cut across Clapham Common in the middle of the afternoon, I came across an entirely naked man masturbating for the delectation of a small audience. That, frankly, is just unacceptable behaviour. If I had had children in tow, rather than a dog, I might have found a stronger word than "unacceptable". It isn't homophobic to object to it .

The truth is that, because gay men are, undeniably, persecuted by some parts of society even when their behaviour is perfectly reasonable and, indeed, not sexual at all, they have hung on defensively to practices which ought to have been abandoned long ago. Indeed, most of them have abandoned them, if my acquaintance is anything to go by. Just because some people out there believe that everything gay people do is ethically wrong, we mustn't leap to the contrary conclusion that we have a right to do anything we choose.

Self-gratification at the expense of reasonable opinion is the curse of the age. Jody Dobrowski wasn't doing anything so very drastically wrong; certainly not wrong enough to justify so horrible an end. But we might consider the possibility that these habits are not just recklessly foolish and dangerous, but just not a very good idea from any point of view.