
It's a good point to highlight. In effect, the same technology could be used to weed out those undermining the democratic process by attempting to inject such compromises, by joining up the metadata, but then that's not in line with Apple's own controlling methods at heart.
But it shows how such scanning technology can be used for whatever Apple decide (or local law decides) is important in the scheme of things. In effect, it shows how easy it is to play God with such tools.