Good point, and perhaps the most important reason this remedy isn't much of a deterrent. That said, once you dispute a takedown request I would imagine (hope!) that the moderating effect of automation is removed, making it easier to prove that element if the requester remains intransigent.

But even without automation, "knowing" is a steep burden when it comes to copyright considering all the legal grey areas.

And it just occurred to me that it cuts both ways--the subsection makes both copyright holder and infringer liable for misrepresentation in takedown disputes. If you make it easier to show knowledge of the copyright holder, you make it easier to show knowledge of the purported infringer. The easier it is to meet this element, the more financially risky is it to dispute takedowns.