That argument sounds rather dark, as the same thing which illuminates the criminals -- guess what -- also illuminates the people. And journalists, lawyers, and associations that digest information for the people.
So now the overwhelming majority of the world goes dark on the law because a minority of uniquely dangerous criminals are lawyer-like Westboro Baptists with bombs.
If terrorists wish to confine their behaviors to the technicalities of western law because they would rather get arrested than shot, that is actually a highly desirable outcome. We should seek to capture all criminals alive and decently, and gather what data they have to attack other networked crime. Seriously, law-conscious Westboro Baptist terrorists would be a positive development.
This is no different from a criminal learning about the circumstances in which a cop might shoot them, and thus opting to drop their gun in certain situations. The criminal is being more legally conscious as part of their strategy.
While wrongdoers who play legal strategy can be a frustrating nuisance, but the alternative is secret legal memos, which I find more frightening.