To be clear, "it works" is not an argument, it is a counter factual, basically evidence that invalidates a previous claim. The argument that author makes was a general "it does not work" and in the very broad definition of works or doesn't work, mass surveillance can be shown to have uncovered unlawful activity that would have gone undetected without it. That is a very technical definition of 'working' and does not address the moral or legality issues of the surveillance itself.

My goal is to help the author make a stronger argument for their cause. And it is stronger to claim mass surveillance has not been effective at countering or uncovering terrorist plots but it has been effective at violating peoples civil liberties and subjecting people to a violation of their right to privacy. Then you have to tie that right to privacy to locally enacted laws or constitutional claims. In the US we've been asserting that mass surveillance is a violation of the 4th amendment which says US citizens have the right to be secure in their persons against unreasonable search. And then we've gone on to argue that mass surveillance is an unreasonable search. With judicial backing like the recent ruling about putting a camera on a telephone pole across the street from a house to keep it under surveillance.

So you have to build the argument from the initial claim to the last one so that each step of the way the listener can understand and agree (or debate) the evidence you present for supporting that claim. That was the form the article takes, laying out its claims one by one to support its call to action to reject the changes proposed in Dutch law.