I flagged this answer as "Not an answer" after reading the guidance linked to from the help section.
I felt the answer could certainly be flagged based on this criterion:
A user wants to reply to the OP, an answerer or a commenter, but doesn't have enough rep, and instead of thinking "maybe there's a reason I'm not allowed to post comments," ignores the help text about what an answer is.
and potentially also on this one:
A user has a related issue and isn't aware of the "Ask Question" button.
(since the user seems to be having trouble implementing the accepted answer and may be looking for help).
However, my flag seems to have been disputed with no reason given, so I'm now wondering what the problem was?
Have I misunderstood flagging in some way?