The user should've properly disclosed his troubleshooting tips with Apple first.
EDIT: /s
EDIT: /s
The blame goes to Apple, no one else.
Stop shooting messagers. What kind of society do we live in where people disclosing wrong doings and crimes are the ones going to jail while the others get away with it.
High Sierra went gold on September 25. Beta 1 came out in June, I think.
The macOS vulnerability was apparently a known thing, POSTED VISIBLY on Apple's own forums, and it reads as if the user got this "helpful tip" from somewhere else.
This is pretty nuts.