I'm not saying that Ukraine must continue because they've invested so much into the fight that it would be awful to stop now. That's the core fallacy, that you owe it to all the past pain and effort to keep trying even if things are looking bad: just because you lost a million men getting here doesn't mean you won't suffer total defeat trying to get to the finish line.
What I am saying is that Ukraine would be foolish not to continue because they're in an incredibly strong position with a track record that defies all odds against a weak retreating struggling foe. Now, it's sure possible that Crimea is a hard target full of Russian loyalists ready to fight to the death, but it's also possible that it's full of Ukrainians who are tired of Russian rule and ready to go back to how things were. I can't know, I'm not there.
Don't quit while you're ahead is a very different thing from don't quit because you've given up so much to get this far.
I can only speculate with zero evidence, but it's possible that the creator has strong feelings about communism, neo-nazis, or reddit, and others involved have other stances.
I don't think the app or Lemmy itself was archived due to technical reasons though, it seemed to work decently enough.