I recently flagged this answer. The question can basically be summed up as:

I want to create a Ubuntu live USB so I can install Ubuntu. How can I do it?

The flagged answer can be summed up as:

Don't. Install the Unity desktop instead.

To be honest I can't see how this answers the core question, i.e. how to create a Ubuntu live USB, so I flagged it as "not an answer".

The flag was declined and I would like to know: what is the motivation behind this decision?

How should I apply the NAA flag more precisely?