While it's true the instructions aren't great and a big botulinum warning should be given for any non-acid preserve process...

This has a really strong "That Happened" feel. In point of fact it's quite hard to culture any given bacteria, almost no one knows rules like this, people engage in all sorts of terrible food safety practices, and the number of actual botulism cases is vanishingly small.

Is it possible this happened? Yes. Is it more likely someone constructed the scenario for reddit karma? Probably.