I find it pretty odd to speculate that they are experiencing a very specific failure mode of a particular database. Do you even know whether they use Postgres?
I know we're already in the weeds, but Malcolm Gladwell’s “Revisionist History” did an excellent episode on the stuck accelerator problem, basically showing it almost certainly didn't happen.
OP specifically pointed out that it's well documented. Every program makes tradeoffs, and I don't think anyone in this thread implied that because Postgres made this one it's unstable or bad.
The specific behavior of Postgres isn't the FUD, the FUD is the speculation that this is what brought down Roblox for multiple days. As others have mentioned, we don't even know if Roblox uses Postgres, and yet we're diving deep on how an edge case of Postgres brought down Roblox. It's the speculation that I think is FUD.