This may also mean that Facebook is complying with the Russian government demands for at-will access to WhatsApp and Messenger content.
As someone in Russia, the block pretty much only hinders use of the legitimate services, not of Telegram. Numerous services exist to allow it to continue, and the block is a hack-job to try to prove a point.
Isn't WhatsApp supposed to be end-to-end encrypted making it next to impossible even for developers (Facebook Inc. in this case) to access the transmitted messages' content?
It does not sound correct.