This was largely how the Mob operated for decades and why RICO was created.
Communications security against national state level organisations in the current environment is a no-win situation for the defending side, you can make their life more difficult but for you to go truly dark means using nothing that shuffles electrons around.
I'd also question how many highly hierarchical criminal organizations exist today and how many have in the recent past. Media and governments love to overemphasize the organized element for simplicity. Likewise many "terrorist organizations" aren't organized either. In practice you mostly see very lose networks that operate a lot like the rest of the economy. There may be some emergent structure but it's usually not deliberate.
> If you where a really high level criminal you wouldn't use a phone at all, you'd pass all your instructions in person to lieutenants who'd pass them on down the chain.
> This was largely how the Mob operated for decades and why RICO was created.
That would be a legal strategy not a communications security one. It may have been more feasible to proxy away legal responsibility before RICO and such.
Yeah, because they want the world to know they are successful criminals. Just wondering: do they also wear a Beagle Boys mask?
I'd also wonder if there's an element of buying access. If all the top people in some criminal industry use it, it may be a way to signal membership.
[0] not that there haven't been numerous whatsapp zerodays and expecting the Signal honeymoon to last makes about as much sense as "there's no Linux/Mac malware"