I think, the reality is that lots of people just downvote, because they disagree with an opinion and don't feel like arguing their position. So, if this explana

I think, the reality is that lots of people just downvote, because they disagree with an opinion and don't feel like arguing their position. So, if this explanation would only be visible to you, I imagine you'd get lots of "explanations" just saying that you're wrong/dumb/etc. This could be a decent solution, though, if their explanation would need to be public. Basically leave a comment in order to downvote (with an indication that this comment was made in connection with a downvote), and therefore then also the ability for others to vote on this person's reason to downvote you.