But also, why does a downvote need an explanation, but an upvote doesn’t?

Because the downvote is for me like criticism. Something is obviously wrong with the thing and i want to know why. I want to learn from it and understand whether i should adapt my behavior or not. And this decision is only possible when i know the reason for every downvote.

Also, because upvotes are harder to explain. Usually there all something like “interesting, hand’t thought about this before”. When you have 20 upvotes, they are probably all very similar.

However, for downvotes it is different. You can downvote things because of:

• factual errors (for instance when some number is relevant but wrong. -> I want to know which number is wrong and the source.)
• missing contextual information (article is negative on topic X, but after knowing Y, it is not that negative anymore and understandable. --> I want to know that.)
• information is correct, but because of bias/stereotypes, the person downvotes. The information in the article explains these things, but the person is too lazy to read that and downvotes before reading. I want to know that so i can ignore the downvote.

etc. So many different reasons to downvote. All of them are important to me.

For me downvotes are a feedback system. So i can differentiate good articles from ones with errors.

If someone doesn’t want to tell you why they like / dislike your comment, they shouldn’t have to.

But what should i do with this feedback? What if its because of bias, stereotypes? and the person is not interested in participating in the debate?

I hate it when people here are downvoting things without explaining the reasons for it!