I'm new here and learning the ropes, so if I'm missing something, please let me know.
I want to know why my answer to this question was downvoted despite the fact that it was correct and I had explained my reasoning. The other short answer (Quark's) had a mildly similar explanation (I also happened to have used the word "rectangle"), but believe me, I didn't steal it from him.
If it was downvoted because it was considered a duplicate, then why wasn't it deleted already? And besides, why are a lot of answers with very similar reasoning (and only mildly similar explanations) upvoted instead?
Edit: just updated the answer.