This is presently an accusation by Telegram, nothing more. Sample of reasons why Apple may be doing whatever they are doing:
1) Telegram is prevalently used by Syrian fighters [1]. (Why they chose Telegram over Signal beats me.) As the Syrian conflict winds down, these fighters are returning home. That creates a security imperative for many governments, including in the EU.
2) Telegram recently ran an ICO that, at the very least, probably runs afoul of American securities law.
3) All of the reasons any app gets held up in review that are not "the Russian government pressured Apple."
TL; DR We have no evidence this is because of Russian meddling.
1) Telegram is prevalently used by Syrian fighters [1]. (Why they chose Telegram over Signal beats me.) As the Syrian conflict winds down, these fighters are returning home. That creates a security imperative for many governments, including in the EU.
2) Telegram recently ran an ICO that, at the very least, probably runs afoul of American securities law.
3) All of the reasons any app gets held up in review that are not "the Russian government pressured Apple."
TL; DR We have no evidence this is because of Russian meddling.
[1] https://www.huffingtonpost.com/entry/isis-telegram-app_us_59...