I have relatively short experience on EL&U and I found some questions where every post was downvoted in a matter of one minute or so. I mean it is very unusual to see every single post in one question get downvoted and I haven't seen them very often since I joined EL&U.
When I first encountered it one or two months ago, I suspected it could be a pure coincidence where a few users are downvoting each of them almost at the same time. But I became a little more suspicious when I saw the following question whose posts were all downvoted, Do we use the present or the past after “when” in a conditional sentence?. Even the accepted answer received two downvotes.
This question, Is there a term for replacing name with a number/code? seems to have the same problem.
Now, I think the followings could be the reasons that triggered the multiple downvotes.
(1) The question is neither good nor on-topic enough (too basic or without context) for EL&U. The message is "You should not have posted an answer to this kind of question."
(2) All the answers are poorly written without good reference or research. The message is "You should not have posted such a low-quality answer."
What is your opinion on this? Is it constructive to downvote all the posts without leaving any comment? The two questions received a total of 13 downvotes and there is not a single comment related with any downvote.
Feature request: Is there any way that I can delete my answer which was accepted by the OP? Would it (deleting my answer) be possible if I flag my answer with in need of moderator intervention and state the reason? I am not talking about the answer accepted by the OP in the second link.