This comment sounds like astroturfing to me. Telegram doesn't even provide secure chats by default. Everybody I've talked to was unaware that the chat was unencrypted until I pointed it out. That's before considering that 1) I don't consider the company behind Telegram in any way trustworthy, 2) the servers for Telegram are closed source and it's unclear what's running there. Signal's server code is open source and the github is actively updated. We also know who works on Signal, as well as their credentials, and they're reasonably trustworthy compared to alternatives.