Telegram is primarily Russian so it's unlikely they would heed American regulators anyway.
Pavel Durov is a Kremlin ally who pretends to be in exile from Russia. The app being sort-of blocked in Russia is just a part of the elaborate PR campaign to legitimize this VK spin-off.
https://theoutline.com/post/2348/what-isn-t-telegram-saying-...
Telegram has shipped blatant backdoors in the past (This one is particularly egregious as there's no way to explain away this MITM feature as a bug) http://habrahabr.ru/post/206900/
Telegram isn't Russian at all at this point.
"Although Telegram was founded by a Russian, Pavel Durov (more on him later), the messaging app rejects any affiliation with Russia."
https://www.nytimes.com/2018/05/02/world/europe/telegram-ira...