I have also been amused by the number of technical people that prefer Telegram vs Whatsapp in terms of security.
The 3-letter US agencies do not have direct access to Telegram's servers, they do have when it comes to Whatsapp (or to any other US-based company). The same goes if you're a Russian doing anti-government stuff in, well, Russia, it's better to put your fate in Whatsapp's (and Meta's) hands, presumably the US agencies won't come after you for being against the Russian government. It's a classical game of arbitration (for lack of a better word).
What makes you think so?
(This is actually independent of you or Signal, I just find it amusing that people throw their security brand™ behind some app and it's just them picking the one they like most of the time.)
Tribalism is a helluva drug.