Encouraging people to explain down-votes
Recently somebody downvotes few of my questions/answers in same time.
Without comment or reason.
Why is this allowed? Imagine this: if someone want to rapidly decrease my rep., simply look at my answers/questions and can start to destroy me very easily.
I think downwoting should be allowed after leaving comment.
I'm open to any kind of objective criticism.
Also, it is polite to explain such negatives to make sure it will not repeat in future.
PS : I already read this but does not seem for me as an answer.