I agree. For one thing it casts the deniers as courageous dissidents.
If instead he'd been allowed to wonder around expressing his views, someone may have shot him in the head by now, putting him out of his deranged misery and doing society a huge favor.
Freedom of speech means the right to say things others find objectionable. Shooting an A-hole just makes him a martyr, and sets a bad precedent.
Nazis and Commies and Islamofascists do that. We have a higher standard.
So do most Western democracies, at least to a far greater extent than the US. Don't get me wrong; I'm a big fan of the US approach, and I'm as close to absolutist on the 1st Amendment as I am on anything. And I agree that attempting to shut down speech just drives it underground, and the more effective strategy is to drag it into the open and counter it.
But America isn't the world; even in free, pluralistic democracies, most people in the world have more faith in government than Americans do. We're fronteir folk. The foundation of our national philosophy came from folks who crossed the ocean at great risk with no guarantees, just to be left the hell alone.
Even Canadians, who are as culturally similar to Americans as anyone elese on Earth, have far more tolerance for restrictions than we do. On the spectrum between freedom and order, there's a pretty broad range that can still be considered free and democratic, and Americans are pretty much outliers at the freedom end of the line.
The facts that most Western (and Westerm-influenced, like Japan, S. Korea and Turkey) democracies accept more restrictions on speech and also tolerate higher taxes in exchange for a more comprehensive welfare state are not coincidental. They're both symptoms of the same underlying cause, that most folks trust their governments more than we do and trust individual initiative and corporate power less.
It's easy to defend the American version of things philosophically, and there are plenty of people who can do it better than I. It's also pretty easy to point at America's unprecedented material prosperity and military power as a sign of its pragmatic value. But the fact that like-minded societies differ from ours by degrees doesn't make them antithetical.
Irving set out to make himself a martyr. He made it his mission to test the law, and he lost. He wanted to be Europe's version of Larry Flynt, to stretch the envelope, but the difference is he chose the wrong cause and the wrong venue.