A subreddit I moderate is shut down. When the other moderator started it, he checked the message showed up for both old and new reddit, and it did. Later, I got a flurry of notifications about join requests, and checked again. The message still showed up in old reddit, but not new. They might have intentionally hidden such messages either to keep people unaware of the reasons for the shutdown or to annoy moderators into reopening, or it might have been that they were A B testing something that accidentally broke it.
AnyOldName3
https://lemmygrad.ml/post/668436 says they're pro-Stalin, pro-North-Korea and pro-CCP, but dresses that up as just pro-Marxism.
Generally, it's a good rule of thumb to see if people list things like worker ownership over the means of production and the abolition of the owning class, or a bunch of authoritarian regimes to judge if they're keener on the communism or the authoritarianism.
As fiction goes, it's relatively plausible - Watney's a good enough botanist to be selected for the space program, and in the bit of the novel/film he's working on potatoes, he's not doing much else, so can dedicate as much time as is necessary to get what he needs. For plot-convenience reasons, he's in a situation where he's got enough space, starter potatoes and existing food to make it all work, too. Andy Weir got those quantities by consulting experts rather than guessing, so they should be realistic.
It's still up for me, but I have to open it with a browser rather than Jerboa. I'll see if I can figure out posting screenshots from this app.