When someone dislikes your post, they dont necessarily feel like debating you, or want you to expand on the subject further.
Sometimes they are having a bad day - sometimes they think you are a dickhead, sometimes they are the dickhead, sometimes they just dont agree with you- or perhaps they have judged you based on previous posts and dont like you.
Other times, someone may dislike your post and tell you exactly why.
Im giving myself 3 thumbs up for this reply.