What does "not an answer" mean?

Question

In the post What does “poke one in the eye” mean?, Yoichi Oishi asks what the phrase means in this context:

‘It seems every step we take, it’s something just to poke us in the eye,’ a frustrated Senate Majority Leader Harry M. Reid (D-Nev.) said at one point this week.

One answer was (and this is the complete answer):

"Poke in the brown eye" is slang for anal sex. 'Poke' is slang for sexual penetration, and 'brown eye' is slang for anus.

I flagged this as not an answer, and the flag was declined:

declined - flags should not be used to indicate technical inaccuracies, or an altogether wrong answer

In every mental analysis I've subjected it to, I can't see that it answers the question. Harry Reid did not say, "It seems every step we take, it’s something just to poke us in the brown eye."

The answer did not state the meaning of poke in the eye, as the question asked.

Since I've had flags marked helpful for multitudes of similar answers, I have a feeling it was just a quick decline on the part of the moderator - perhaps they didn't see that the answer only addresses poke in the brown eye.

What does not an answer mean?

Answer 1

The original question does ask about the meaning of "poke in the brown eye":

I searched the definition of this phrase in dictionaries at hand and online dictionaries, none of which has entry of this phrase, except for Online Slang Dictionary carrying the phrase “poke in the brown eye” without giving any definition of it. I’m also curious to know what “poke in the brown eye” means.

(Emphasis added by me)

So Bacon Bits' answer is an answer, albeit focusing on a side point.

It might be valid for someone to write a better answer than both Bacon Bits' and the accepted answer, so that it answers the whole question.