Your logic: It's not option 1 or 2 (statement is unsubstantiated - when you say it "was objectively not very good," you really mean "in my opinion it was not very good"). So it must be option 3 (also unsubstantiated), since option 3 is the only option left (unsubstantiated).
To answer your last question: 1) As far as I know that kid did not hold any high-ranking role at the company anymore; the talent probably lay elsewhere. 2) There are many reasons and unless your name begins with Marissa and ends with Mayer, you cannot know for sure.
To answer your last question: 1) As far as I know that kid did not hold any high-ranking role at the company anymore; the talent probably lay elsewhere. 2) There are many reasons and unless your name begins with Marissa and ends with Mayer, you cannot know for sure.