I'm not quite sure which case, I think it was about activists (not sure tho), but these fact were indeed used as an argument to support the idea that they were terrorists, because they're trying to hide something
The fact that you care about privacy means that you are hiding something which means that you are now a terrorist.
Closer to "we think you are terrorists, but cannot prove it because You've encrypted all the relevant sources of evidence. Therefore you must not only be hiding something, but hiding evidence that you did what we accused you of, which is clear evidence that you are a terrorist, or else you wouldn't be hiding the evidence of your terrorism from us."
Which is if anything even worse, since it presupposes that any accusation made is definitely true by default. Guilt until proven innocence has a bad track record.
"They indicted 7 people for Terrorism last year, in part because they encrypted their disks, used tail as their OS and signal for communication." would work maybe.