I have seen various down votes on my answer, without stating what is the problem with it, in last days. Similarly, I have seen some down votes on some questions/answers of other people without explanation. I mean, down-voting is normal, but it's also good to comment and let the user know what is the problem in the post rather than silently down-vote, am I right?
I mean, is it not helpful to the user if he is not aware of the faults of his post so that it can be improved.
That has been implemented. When a person down votes, a pop-up message shows
This encourages the user to add a comment.
Take a look at : Encouraging people to explain downvotes on main meta.
Some people simply don't want to spend the time that is needed to justify their downvotes with the comments.
While an unexplained downvote might seem not helpful, it still is as it voices the opinion of the person that something with this answer is wrong.
I used to always comment with my downvotes on Stack Overflow. I quickly found that people don't like constructive criticism and will get hostile in the comments and revenge downvote. Granted, only a tiny fraction of people react this way, but when they do it's annoying enough to make you never want to comment with downvotes again.
In any event, most of the time it should be obvious why the question did not show any research effort, was unclear or not useful, and then the comments are just noise.
Interestingly enough, after have some conversations and reading about this question (that is a valid question, and was downvoted!) I decide to read again the Help from Stackexchange.
It's available here: https://stackoverflow.com/help/privileges/vote-down
And I could rephrase it all, but just quoting it is sufficient (with some bold and italics made by myself):
When should I vote down?
Use your downvotes whenever you encounter an egregiously sloppy, no-effort-expended post, or an answer that is clearly and perhaps dangerously incorrect.
You have a limited number of votes per day, and answer down-votes cost you a tiny bit of reputation on top of that; use them wisely.
What are the alternatives to down-voting?
The up-vote privilege comes first because that's what you should focus on: pushing great content to the top. Down-voting should be reserved for extreme cases. It's not meant as a substitute for communication and editing.
Instead of voting down:
If the post is spammy or offensive, flag it.
If the question is duplicate or off-topic, flag it for moderator attention.
If something is wrong, please leave a comment or edit the post to correct it.
