Apparently I was the mod who declined your flag, but it was several weeks ago and I really can't remember why. Probably I declined it because I didn't consider the answer worth deleting and hadn't yet got into the habit of sometimes marking flags helpful even when not deleting the answer.
It lacks formatting. It lacks basic syntax. It even has this little tone we try to remove from answers (starts with "C mon guys, it pretty obvious......." and ends with "Nerdy captain flies off.")
None of these is a good reason to flag an answer. If you see an answer that's poorly formatted or contains unnecessary commentary, the best course of action is to downvote it or edit it. If you see an answer that makes no attempt to answer the question, then flag it as "not an answer" (and vote to delete it if you have enough rep to do so). See also this post from a CM on main meta about non-answers, and the following amended picture courtesy of Undo:
I can see, however, that you didn't flag as "not an answer", but as "very low quality". Unfortunately the workings of the "very low quality" flagging system are pretty unclear, and a lot of people agree that it doesn't really work very well. "Not an answer" is relatively easy to define, but "very low quality" is much more subjective and it can be hard to decide when to delete an answer flagged as such.
General theorising aside, looking at the answer now I definitely agree that it is very low quality. Whether or not I deleted the answer, your flag should have been marked helpful.
But a single flag won't make a great deal of difference in the long run; the vast majority of the flags you've raised have been marked helpful, so it's not a big deal.