Any time i heard or see post talking about down voting, I think of crop pests, Caterpillars, grasshoppers that distroy crops.
Down vote, makes efforts waste when taken all time to write a post. It could make someone to be depressed especially for newbies, I don't know how others feel when they take there time to write something reasonable to the community and get down voted or get low vote. Sincerely, it would make someone feel like not posting for the next day.
Bad content is one of the reason why people get down voted, and I don't think it should be among the reason because every one's writes from his brain and we can't all have the same knowledge or have the ability to write to the interest of the readers.
Bad content can be corrected by letting the author know, in other to correct him/her self by dropping a comment on the post, I'm sure such will not repeat himself again rather than down voting, I'm not say we should not down vote, I'm just suggesting the way to correct our selfs here.
I'm sure some would have left the community or had bad feelings about it because of down voting, though some don't care if the community improves or either its increasing in number but I'm concerned because I really want the community to improve.
The recent record shown by @achimmertens convince that the community is progressing.
The main thing we should be frankly dealing with is plagiarism, and I think that has reduce.