Technically, that wasn't a Telegram issue. Telegram supports 2FA with an user-configured password. Dallagnol & co weren't using it. They were thus vulnerable to

Technically, that wasn't a Telegram issue. Telegram supports 2FA with an user-configured password. Dallagnol & co weren't using it. They were thus vulnerable to voice mail hijacking, SMS hijacking, and other carrier-based attacks. I agree Telegram's UX could be better but the app isn't to blame if technologically illiterate users are relying on it to circulate high profile confidential info.