Instead, we should spend hundreds or thousands of man-hours engaging with trolls? At least Roko had a positive goal.
From your link:
This about the Internet: Anyone can walk in. And anyone can walk out. And so an online community must stay fun to stay alive. Waiting until the last resort of absolute, blatent, undeniable egregiousness—waiting as long as a police officer would wait to open fire—indulging your conscience and the virtues you learned in walled fortresses, waiting until you can be certain you are in the right, and fear no questioning looks—is waiting far too late.
Note that you're excluding a middle that is perhaps worth considering. That is, the choice is not necessarily between "dealing with" a user account on an admin level (which generally amounts to forcing the user to change their ID and not much more), and spending hundreds of thousands of man-hours in counterproductive exchange.
A third option worth considering is not engaging in counterproductive exchanges, and focusing our attention elsewhere. (AKA, as you say, "don't feed the trolls".)
If it's worth saying, but not worth its own post, even in Discussion, it goes here.