I would have done exactly the same thing. He is using a SCM that deleted all its files due to a bug. He tried to recover its deleted files, and it seems the next commands utterly killed any hope of recovery. What was him supposed to do? keep in its mind perfectly the internal state of Fossil after an unknown bug to find which command, if any, could recover its files? I would have panicked, tried every command I could think of and started crying.

After Fossil deleted its files he informs the maintainer of the bug, giving a clear description of what happened, and decides to switch to a more mainstream SCM.

I don't get why you're giving him so much heat. He seems to me constructive (the bug was fixed) and mature (he went to a more mainstream SCM that is less likely to have some kind of "never seen before" bug while you just "make a branch").