text: Q:
  
  Down-voting and no comments
  
  In these sites, down-voting has become a passion to prove intelligence. Yesterday, I got two upvoted answers downvoted simultaneously (Someone has down-voted both within 1 min). I think they're too busy in leaving comments and reading Etiquette
  Why isn't there a rule: "For Downvoting upvoted posts, comments are must"
  The posted users don't know "For which silly reason, they've been downvoted..."
  Then, how would we correct the answers? Only one choice left out: "Answers must be deleted".
  
  A:
  
  The reasons you're not required to leave a comment when downvoting, and why that is not going to change, are explained in detail in many questions on Meta Stack Overflow (example).
  When you downvote a post, you're encouraged (but never required) to explain what can be improved about it. Of course, this is also encouraged even if you don't downvote the post.
  Coming at it from the other direction, when your post is downvoted and/or someone suggests an improvement, you have no obligation to do anything about it. Correcting the answer or deleting it are not your only choices. You can just leave it alone.
  
  