But why say they have no plans to shut down and link directly to the part of their FAQ where they say they will shut down if they are under government surveillance? Why not just tweet something like "We have heard your concerns" or something similar
You might not be able to shutdown if you have been forced to keep the service running.
The purpose of the hyperbole, I'd assume, is to make one ask the same questions you're asking. In the philosophical sense: if we have to ask, we already have our answer.
Maybe they lost access to their infrastructure and twitter account. Who posted this (to-date) last message? Better be cautious, activists.