At various times, most social media platforms have received criticism for alleged failure to prevent distribution of copyright-infringing content. Few, however, have been threatened with widespread blocking more often than Telegram. In a row that seemed ready to boil over last year, Telegram was given an ultimatum by the Malaysian government; come to the negotiating table or face the consequences. A Malaysian minister now says that Telegram is ready to fight piracy.
I don’t get what you’re trying to say at all. If a party is in a group chat and reports it, they can provide their credentials to Signal to enable Signal to view the contents of the chat.
Yes, they’re a carrier that does not know the content of what they carry. But once they are made aware, the legal system considers them to now bear responsibility if they don’t take action. Whether or not that’s fair is a pretty large topic, though I’m inclined to think so myself.