They didn't just put out Docker with a sign up that said "free stuff" though. They actively solicited the users; they told the community "Hey, use our software, you can trust us". If you do that you do have an obligation.

It's like, if you beg your friend to let you give them a lift and don't show up, you can't turn around and call them a "choosey beggar" because the lift was supposed to be free.

The response in that thread isn't _remotely_ reasonable, of course you can't make a developer tool like this auto-update.