[wott]

I don't see it as an exception, but rather as a matter of priorities.

It means "(more) than (one TEDx talk)" and not "(more than one) (TEDx talk)s".

And it works the same way in one of the author's native languages. It is even more obvious and you cannot get it wrong in that language.

Also, the definite article is used in this language much more regularly than in English. The problem with English is that, on the contrary, it does not use it everywhere. So you have to drop it sometimes, but not always, and the "rules" can be a mystery for a foreigner.