I keep seeing people make really interesting posts, and then someone will reply pointing out a minor error, technicality, typo, or just call part of the above post "wrong" while spouting off an irrelevant personal opinion. Those I downvote.
Unfortunately, on the internet in general, you see that all the time. Someone makes a long, interesting, and thoughtful post with a lot of ideas and content. Then someone else writes a one line criticism that picks apart 1/100th of the previous comment's content, and then everyone upvotes the correction and downvotes the original for being "wrong" on something.
Really people are just too lazy to read long posts and certainly too lazy to think about them. So a lot of people skip over them and read the first reply to see if they are worth reading. They then see the correction, upvote it as they feel as if that person "saved" them from wasting time reading the long post, and then move on (or worse downvote the original comment).
Essentially people will downvote a long comment without having ever read it and will upvote a correction without a clue how relevant it is. It literally happens all the time.