The implicit demand is to stop supporting fascists.

Yeah, they wanted change. But then the fascists conveniently swooped in and pretended they offered the type of change people actually wanted. (Cheap eggs, etc.)

It’s good, but it’s centralized. Let’s say an authoritarian regime shuts down the central Signal servers. Then what?

You’re ignoring the thing about federal election funds. Is attempting that goal a “waste?” By that logic, in a solidly blue state, voting for any major party candidate is also a waste because you as an individual can’t impact the outcome.