A roar of libertarian outrage greeted David Cameron's announcement this week that the government was going to talk to internet service providers about installing opt-in rather than opt-out filters for pornography, as if computer access to hot and cold running arousal aids was some kind of basic human right. Is this really such a big deal? Under the current arrangement, people who don't want porn on their computers are obliged to take action. Under this proposed new one, the onus would fall on people who do. Either way, it seems to me, all that is illustrated here is the old adage that you can't please all of the people all of the time.

A lot of the criticism has focused on the practical impossibility of developing adequate filters. Teenagers in puritan households may find themselves unable to access desperately needed information on sexual health. Right; but isn't it reasonable to assume that the computers in puritan households have filters on them anyway? Children in such households surely do as they have always done – and get their information via other means, or from a peer with more access. If they are so isolated that they can't do this, then it's hard to believe that their sexual health is under great threat in any case.

Other critics have pointed out that one man's porn is another man's harmless fun. People will still have access to page three "girls" in the Sun, even with the filters on. OMIGOD! That makes the virtual world a bit more like the real world, in which you have to sit looking at knockers if the person opposite you on the tube has managed to achieve the not-inconsiderable feat of finding something fascinating on the Sun's page two.

Sometimes I find the concept that the internet is a brave new world of unsullied freedom unbelievably silly. The internet is just another part of man-made reality, not some separate utopian civilisation where humanity has the chance to start again. Perhaps some of the warriors for internet freedom would have, last century, been picketing newsagents, insisting that their topshelf policy for gentlemen's magazines discriminated against the short.

Louise Mensch, the former conservative MP, bless her heart, has voiced her worry that the possible banning of rape simulation footage will ruin the fun of half of all women, who commonly enjoy rape fantasies. This is indeed a worry. I wouldn't know where to begin, conjuring up a rape fantasy from my sadly inadequate imagination, if I hadn't seen a useful film to inspire me beforehand. We wouldn't want the human imagination to be left to run riot, when technology can provide off-the-peg non-consensual sex. (Anyway, it seems that prose will be excluded from these as-yet-imaginary filters, so women will still be able to pick up some useful tips on fictional rape. Hurrah.)

My favourite argument against porn filters, however, is the one that warns that they're a threat to marital harmony. Internet porn-consuming partners would have to confess their proclivities to their non-consuming partners, thus igniting rows. At the moment, such monumental outbreaks of domestic disharmony are only in danger of occurring when one partner wants to install a porn filter. In other words, the current situation is awkward for some people who don't want a portal to porn in the sitting room, while the proposed one would be awkward for some of those who do.

Why should the convenience of the second group be so much more important than the convenience of the first? The implication is that it's normal to want access to porn, and abnormal not to want access to porn. Yet it's clear from much of the criticism that using porn is the sort of normality that people have some reservations about sharing with others, even the people most close to them. Why would someone hide a healthy fondness for porn from their sexual partner? The tenor of this whole debate suggests that somehow it's unfair to put people in a situation where they're obliged to be an active participant in their quest for porn, when the responsibility for policing porn in the home is currently resting comfortably in the hands of those who would prefer never to think about it at all. It's almost as if liking porn is secretly considered, even by its greatest enthusiasts, to be some kind of disability, a disability that it would be morally wrong to fail to do everything possible to help people accommodate as simply and straightforwardly as possible.

The most shrill complaint against Cameron's wheeze is that it's "censorship". This seems to me like saying that not placing a copy of Anna Karenina in every home, pre-web, was censorship against Russian novels. No one is telling people that they aren't allowed to access porn on the web. They're saying that in order to do so, you have to tick the box pretending that you've read the terms and conditions. And why not? Even in the highly sexualised public spaces of contemporary Britain, there's still broad agreement that footage of people humping shouldn't be up on a screen at Piccadilly Circus. There's absolutely no reason why the internet should be any different.

It's perfectly reasonable for the owners of computers to be expected to make an active decision about whether porn is available on the computer, not whether it isn't. At the moment things are set up so that the consumption of pornography is made as passive and easy as possible. But that's not right – because it flies in the face of a robust consensus that says porn is for adults only, adults who should be actively aware, when they've got next door's 11-year-old in their house because their mum's late home and it's raining, that their computer is primed for anal.

And as for all the folk saying that the idea is risible, because paedophiles will laugh at it? Dear, God. Don't we already spend enough time faffing about doing things because the existence of paedophiles obliges it? (I speak as someone who just had to get CRB checked so that I could go camping with my son and his schoolmates. Obviously, I wouldn't need to be CRB checked if I was planning to wait in the bushes until one of them was on their own and grab them.) This isn't about paedophiles. It's about trying to bear in mind that there are children in this society as well as adults, and that there are adults who find all porn upsetting and should not be disregarded or discounted because of it.

Frankly, it's irksome to me that I've had to write this piece, which is essentially an appeal for calm in a climate that says, with a baffling disregard for the view of the vast majority, that the right to porn must be universal and that access to it must be protected from all possible inhibitions. Maybe Cameron's idea is a lame duck. Let's face it, they usually are. But the level of indignation over the fact that the prime minister is even thinking along these lines is weird.