I think his point was _precisely_ that it was a stupid mistake on his part, and not a 'master hacker' subverting his defences. But I agree it's odd that he does

I think his point was _precisely_ that it was a stupid mistake on his part, and not a 'master hacker' subverting his defences. But I agree it's odd that he doesn't seem to have heard of defence in depth, and relied entirely on one UFW rule as opposed to also setting a password on Mongo and/or (preferably) configuring firewalls on the cloud provider level.