It is consistent with rest of fediverse that doesn't have down-votes but has emoji-reacts. misske, wafrn and others count them as likes, and likes are upvotes.

Iirc the development was just whatever could most easily be accomplished, and then once that's out, the rest becomes less urgent and offers diminishing returns in exchange for additional effort.

One crucial detail is that ~99% of all Threadiverse users are on Lemmy rather than PieFed (conversely, >99% of Fediverse users are on Mastodon rather than either, or Friendica, nodeBB, Pixelfed, Loops, etc.). So part of the decision I thought was how to structure these so as not to break Lemmy - like if something is neither an upvote nor downvote, how would that affect Lemmy users?

Tbh I wasn't deeply involved in making this feature so the last point there is my attempt at a hypothetical scenario by way of explanation, which may not strictly speaking have been an actual valid consideration - or rather I am saying that my words here are not all that precise.

Many features on PieFed are unpolished like this. Additional contributors and/or funding would he necessary to flesh them out more. Like hashing out an agreement with Lemmy how their side of this would work. And I suppose with Mastodon as well.