Has immigration control become the answer to everything? For David Cameron, it is the answer to how to deal with British jihadists who wish to return to the UK. And for an internet campaign, it is the answer to dealing with the odious pick-up artist and “guru” Julien Blanc.

We mustn’t expect Cameron to reconsider his perspective. He is running scared of Ukip. However, for those backing the campaign to get the home secretary to ban Blanc (which had well over 100,000 online signatures at time of writing), the comparison might give pause for thought.

Call me old-fashioned, call me a sexist, call me an apologist; hey – I expect Blanc would divine I’m gagging for a call. But just because the home secretary has the power to ban someone doesn’t mean she should use it or that she should even be asked. Crikey, even the Bush administration let Mahmoud Ahmadinejad into the US in 2007 to make a speech at Columbia University.

It’s one thing for those who take righteous issue with Blanc’s demonstrable misogyny and racism to apply commercial pressure. That is what happened this week, when another web campaign persuaded ITV2 that its relationship with a fellow by the name of Dapper Laughs was no longer worth it. Oh Dapper! We knew you so briefly. To watch Mr Laughs stuttering through his penitential Newsnight interview, sounding like Joey Essex’s less intelligent younger brother, was to wish to look away in embarrassment. This was a victory against a man so small that the victory itself should not be described as anything other than small.

Nothing wrong with that, I should emphasise: a victory is a victory, and it all counts in a world where street harassment is an unacceptable menace. But convincing ITV2 not to recommission a show no one really watched anyway ain’t Roe v Wade, and you can be sure that those who defend the big injustices against women will be perfectly happy allowing what is becoming excessive celebration of this affair to continue as long as it likes.

As I say, that’s commercial pressure. But pressure on the home secretary to use discretionary powers is a different matter, and should be subject to two distinct sets of considerations.

The first is rooted in principle, namely the trade-off between liberty and security, in which so-called security has too often prevailed in recent years.

It may be more complex than clicking on a petition, but those demanding Blanc be banned ought to ask: has a crime been committed? If it has, then the campaign should focus on demanding it be investigated. This would be a far worthier course of action, as it might see Blanc held to account for his actions. He might have a case to answer in Tokyo, where his videos appear to show him approaching women on the street and shoving their heads toward his crotch. If so, these films must be highlighted as pieces of evidence and the Tokyo authorities urged to investigate. Ditto with any similar films made in other jurisdictions.

The second set of considerations is practical, and it is here that the campaign feels especially wrongheaded. There’s no need to point out that this is the age of the internet, given that is the very medium of the petition. But there does appear to be a need to point out that, in the world that the web has shrunk and interconnected more closely than before, a ban is next to pointless. Ideas do not have borders. You do not stop someone from saying things and having them heard by not letting them visit somewhere – if anything, you make them into the cause celebre they so transparently long to be.

Bans turn ranting clerics you’ve never heard of into ones you suddenly never stop hearing about, and a ban could easily turn Blanc into a guy who doesn’t even need to turn up to dispense his rancid ideology. He could simply hire a London venue and be beamed in from the States – and get twice the coverage off the back of it. His followers – who we can only surmise already suffer from feelings of alienation or they wouldn’t need to pay him huge sums to help get them laid – will feel even greater solidarity with their outcast overlord. He’ll be a pick-up martyr.

As a lesson in self-defeat, it would be trumped only by Cameron’s latest plan, which I expect he thought would fall on more traditionally hardline ears if he announced it in the Australian parliament. (Incidentally, Australia had just revoked Blanc’s visa). The PM’s focus is on another sort of martyr, or rather those who’ve decided the career of martyr isn’t for them after all – the young jihadists who bound off to Syria, only to get there and find things slightly different to how they looked in the brochure. Is banning their return the reaction of a grown-up, responsible state? Or, as Liberty neatly summarises, “dump[ing] your citizens like toxic waste into the international community”? Either way, Cameron deems the posturing of a ban to be more valuable then any intelligence that could be gleaned from returning jihadists. Make of that what you will.

In the end, I hope you agree immigration control as anything other than a means of making us feel better about these things does not work. Indeed, if I had an invitation for Blanc – and he thinks women are sending him invitations all the time – it would be: come on over to Britain, mate, and let’s see your act.

That act would be engaged with by women and men, from bloggers to columnists to tweeters. Secret recordings of his guru-ing sessions would be made by hacks and enterprising citizen journalists, giving the public the right to decide precisely what sort of chap Blanc is. I don’t think it would be beyond the resources of the Met to stick a police officer in each of his events, or to tail his filming activities on the basis that they may pose a threat to public order.

If he breaks the law, then let him be dealt with by it – not by a visa ban. Let Britain be a place where the rule of law is mightier than immigration control.