They specifically mention open kettle canning as a bad practice. My friend and I were canning something and he wasn't sure we were doing it right. He called his mom and she said she had always done open kettle canning (where you basically just pouring boiling temp food into hot jars and seal them). I guess experts have soured on the practice.
Either way, we made our cans the "right" way after lots of googling and none of the jars seemed to fail.
While I sympathize with the moderators, I would assume that historically most subs are not moderated by experts, but yes, a decrease in quality mods and mod tools will choke reddit to death.
