1
This is due to the nature of the Fediverse mostly. Kbin, lemmy and other platforms all exchange data with each other using a standard that's meant to be flexible, but has a lot of ambiguity. As a result, to accommodate the vastly different platforms (not just kbin or lemmy which are the Reddit-like platforms), some of the design decisions end up with behavior that doesn't quite fully mimic the large social media platforms that many of them try to emulate.
In this regard, upvotes are actually using what's known as a "Like/Favorite/Star" to represent them. These by design, are a way to let the creator of the content/post/thread/microblog/etc know that you "like" their content. In kbin, instead of showing it as a number of "likes" or "favorites" as on other platforms, shows as the number of "Upvotes" on a thread, or post. Lemmy also uses "Like/Favorite/Star" for upvotes.