As referring to "you can't answer the majority of the questions" or "you're working or intend to work as a software developer". I read it as the latter, but I guess it could also be read as the former.
The intention was "why don't you know these things", in the sense of "I really think you should go out and learn / re-learn these areas, because I think it's very likely that knowing them better will help you produce better code".
> you should ask yourself why
As referring to "you can't answer the majority of the questions" or "you're working or intend to work as a software developer". I read it as the latter, but I guess it could also be read as the former.