Wrong answers are answers, even if you don't like them
Here's what the not an answer flag definition is:
This was posted as an answer, but it does not attempt to answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.
Generally, the not an answer flag is reserved for posts that do not even attempt to answer the question at all. There are practical reasons for this:
Allowing not an answer flags to be used for posts that you simply disagree with (even if, to you, they're obviously wrong) means that moderators have to make a technical judgement on the post. In effect, moderators become the only users to decide whether your post is 'right' or not, which is difficult to judge, especially for a topic like literature.
Stack Overflow has already struggled with inappropriate NAA flags (although mainly in the context of link-only answers, or partial answers). The Low Quality Posts queue tends to encourage people to delete everything that could be described as low quality, which is perhaps too extreme.
If a post attempts to answer the question, it is not worthy of flagging and deletion. Downvote incorrect, misleading or low quality answers; edit if you can see a way to fix them and comment to let the author and others know what's wrong.
The system already has a way of showing users the best posts first, and those which are more controversial sink to the bottom of the page. This is good—it means that there's no need to delete answers which aren't as good, because the post's score is obvious.
Save your flags for posts that really shouldn't be here, like gibberish, questions/comments in the answer box or other weird posts. Otherwise, let people have their voice, and allow the voting system to do its job.