"Meddling" with Russian elections is a pretty strong statement, they just followed what Apple and Google did, and there was lots of discussion on HN: https://news.ycombinator.com/item?id=28655937
Telegram is not E2E encrypted by default, so the other comment makes sense.
Nope. WA uses server-side group management, with Signal its purely on user-side. The message is revealed to be a group message on client-side. In theory, since the group messages are a burst of packets of the same size, the server can distinguish between messages to groups,and drop them if it wants to, but that would be interference of communication which, IIUC, is a felony.
Telegram is not E2E encrypted by default, so the other comment makes sense.