Whenever I glance at darknet forums, people there always use Telegram for instant messaging. This seems like a strange choice for their use case, considering that Telegram is neither secure nor private[1], being centralized with Russia-controlled servers[2], phone number registration, no encryption for personal chats by default in mobile client and no encryption at all in desktop client[3], etc.
So why do they use Telegram instead of actually secure and private alternatives, like Delta Chat, XMPP+OMEMO, etc.?
I guess that you only see the tip of the iceberg in these “darknet forums”. They probably favor visibility for the end-user instead of security, due to their target audience. XMPP and GPG is pretty popular on DNMs.