It’s very nice to see that X people liked a post/comment and Y people disliked it instead of just having a singular “goodness/badness” rating. It (literally, in a mathematical sense) adds a whole new dimension to post ratings and gives us a more nuanced understanding of people’s opinions. Plus, it feels a lot better to see that 5 people agreed with you and 7 disagreed when you made a controversial statement instead of just seeing a score of -1 telling you how bad you are.
It’s an integral part of online content, being able to both upvote and downvote. I’m amazed how it’s still so divisive given that it’s been the norm for over a decade on Reddit