How the hell is that unique either in "MSM" or online media? He basically just described Gawker, BoingBoing, DailyKos, and a slew of other "hot take" sites. In terms of traditional media, every city has the garbage tabloid-level paper.
Is Running the New Smoking?
I like Matt Yglesias, I think his Very Serious work is usually at least interesting, and I find some of his trollish witticisms very appealing. But I think you've hit the nail on the head; he creates a sort of Poe's Law situation around his own work because of them.
In this case I think he's overreaching a little.
But then I also think the lab leak theory was discredited and avoided partly from well-meaning applications of the wrong reasons, because even if you make a serious review of it as a professional accident, the Wrong People will definitely like and share your work for their own awful/vile/violent reasons. And nobody wants to be part of that.
I wouldn't blindly adopt a Slow Boring headline as my own opinion because Matt Said It, but I wouldn't do that for any other opinion-haver either.
I'd rather have a well-argued contrarian take that the author doesn't really believe, than a badly-argued one that the author genuinely believes.