Feds can request info from Telegram. Additionally, Telegram has evolved past a simple messenger application. A massive amount of projects, most of them being crypto projects, use Telegram as their primary method of communication and announcements. It is also a very popular messenger in India and parts of Europe. They can block Signal because they can get away with it. If it means banning a bunch of CSAM traders and drug dealers, even if it includes a few users and privacy nerds, they're still winning in terms of easing up their moderation efforts without significant outcry. I believe this block will be lifted, even if Signal users a minority, they are a loud minority. This could have very well been a mistake.