Their argument doesn't appear to be "Tor is bad because it can be used for bad stuff" but "Tor is bad because it is overwhelmingly used for bad stuff today". That seems to be a meaningful distinction to me.
(I don't really care about the argument/premise itself, I just find your sloppy attempt at a counter-argument to be weak)
Since we're talking about the devil: The biblical standard for acceptable collateral damage is kind of interesting. God in the old testament said he wouldn't smite a city if there are at least 10 righteous people in it. /theologynerd
There's a much different notion of God in that passage (and much of the Old Testament) than most have now. The number 10 is arrived at after Abraham persuades God to lower the standard from 50. There are at least a few stories where mortals persuade God to change his/her mind.
Of course, him being God he would've probably known the exact amount of righteous individuals in the city. Not to mention being able to define 'righteous'.
That said, I've always been very fond of the passages in the OT where individuals managed to 'change' God's mind, as well as the general human emotions he appeared to have.
No, it argues that the Tor hidden services that the author knew about were overwhelmingly used for bad stuff. This is problematic in two ways: the methodology of gathering addresses was pretty suspect, and it glosses over the fact that the VAST majority of Tor traffic is headed to the open Internet, not a hidden service.
If you're looking for a shoddy metaphor you should probably use swords instead, because the legitimate uses of knives vastly outnumber the killing-people uses of them but swords have it the other way around.
(I don't really care about the argument/premise itself, I just find your sloppy attempt at a counter-argument to be weak)