how do you win by not playing
You win by not losing at least. Because everybody who plays, loses eventually. If a loss would equal a minus point, someone who doesn't play would stay at zero, which would automatically be better, statistically speaking. Of course one might argue, before you lose, you were the last poster, so you win at first, getting a plus point, but as soon as somebody else posts something you lose and this point is removed, bringing you back down to zero, while also making you a loser of this game. Someone who doesn't play is also still at zero, but hasn't lost yet, therefore has a slightly better standing than someone who joined in and lost. Of course, none of this really matters at all, but technically this is how not playing would be more beneficial.
It's a bit like "The Game"... By the way, I lost it and so have you!
The rules are simple:
Rule 1: Everybody on the world plays it by default.
Rule 2: The moment you remember (or getting aware of) the game, you lose it.
Rule 3: If you lose the game, you have to announce it, which in turn makes others encounter your statement to lose it as well.
Rule 4: If you lost the game, you got half an hour to forget it and get into the game again by forgetting it. If you need more time to forget it, you lost once more.
So the winning moves are similar: The only winning move is not to play, not to engage, not to think about it. The game is unwinnable by design. You can't win, you can only try to avoid losing it by either being unaware about it or by dying, as grim as that sounds, before remembering it again, which prevents you from losing it ever again.
This game here is similar, unwinnable by design, so you can just try to avoid losing it by not participating, or you have to constantly spam the thread in order to stay atop everybody else, or you need to have a good premonition when it comes to server downtimes, so that you can post the last post on the thread just at the right time that nobody else would be able to beat you to it.
So, nobody wins (permanently), but most people lose, unless they aren't playing after all.