Mayor of London Sadiq Khan delivered a remarkable speech at the South by Southwest, or SXSW, conference on Monday — remarkable for bad reasons, not good ones. He said that he wants social media companies to crack down on free speech.

Following his speech, Khan was interviewed by HuffPost editor Lydia Polgreen, who at one point asked how we can be "better citizens in our global democracy" (and people wonder why Trump won!), Khan offered thoughts on Trump and his war on Uber. But the most telling moment came when the mayor stated that "As a former human rights lawyer, I'm a big advocate of free speech. This isn't about depriving people of free speech, this is about inciting hatred."

Here Khan, inadvertently, shows his minds eye, because "inciting hatred" means very different things in Britain and the United States. And the inherently subjective nature of that definition explains why it rightly is not restricted in America. We reject self-censorship on debates of public concern. Yet Khan's demand cannot simply be ignored.

After all, social media companies operate at a global level, offering instant communication between users in London, Lagos, Berlin, Baghdad, and Kansas City. And that's keenly relevant in the context of this line in Khan's SXSW speech.

"What we need to see is a stronger duty of care so that social media platforms can live up to their promises to be places that connect, unify and democratize the sharing of information." Khan continued, "And be places where everyone feels welcomed and values. If this doesn’t happen, then more countries will start to follow or go further than what Germany has done."

Here Khan is referring to Germany's waltz with its past, in clamping down on speech that breaches the constraint of authoritarian orthodoxy. But what Khan really wants is for social media companies to subjugate their content standards to European legal codes. That would smash, to borrow from Polgreen, "our global democracy." Social media companies cannot efficiently restrict speech in Berlin but not in Baltimore? Yes, it could technically be done, but the costs would be dramatic and the benefits negligible. It would slow down the speed of information sharing, lead to self-censorship and thus fundamentally undercut the existential purpose of social media companies.

That concern, not deluded laziness, is why Twitter and Facebook are so reluctant to undertake the action Khan seeks. Still, Khan's ignominious wrath is arrogantly misplaced even in its motivation. According to the mayor, unless we take his advice, social media speech will "lead to young people becoming socially disenfranchised," and deterred against seeking public office. Referencing the abuse he himself has received on Twitter, Khan asserted that it "shouldn't be a question of how strong I am or whether I can withstand that..." but instead that social media companies can restrict that speech.

I fundamentally disagree. If you are a politician, journalist or any other public figure, you must accept that the virtues and benefits of a free society are far more important than your own hurt feelings and personal discomfort. Put simply, you should have the intellectual courage to withstand the unpleasantness that sometimes rides the wave of vigorous public discourse. The greatest extremist threat we face is not that of the mindless bigot, but that of the politician who seeks restrictions on what can be said and seen on matters of public concern. Fortunately, the founding fathers of the U.S. understood this and established a constitution to defend against it. From time to time — as now — it becomes evident that this was a very good idea.