These small factions of complete assholes put a stain on encryption technologies that governments like to point out. I still think that everyone should have easy access to high quality encryption. While it can be enabling for groups like this, the nanny state alternative we continue to move towards is ultimately worse.
As in - invading Iraq wasn't terrorist apparently. 15 years ago from the news it seemed to have produced a backlog of war crimes to be investigated for like half a century (maybe exaggerating), but in fact the investigations stopped as soon as public attention got saturated.
I've heard the Artsakh Defense Army being called "bandits" and "terrorists", and they are all my brothers (if they want that).
Still, to those "terrorist" bros who really use it I'd advise to move asap to something which is not snake oil. Again, Signal, or DeltaChat, or whatever else they find, just should do some research.