Fediverse

It does. I will never use an instance without downvotes. Nobody liked it when youtube downvotes were hidden.

I have a very controversal piece of software for managing Lemmy that I posted about. It's mainly for personal instances to sync defederated lists from larger entities. I.E. I want to own my account (or small group), and while I would use this larger site, I will use my own to spread the load, but trust the admins' judgment.

If it weren't for down votes, from the post listing page users would think it was a huge hit, and not realize there is a healthy debate about how to use it, why, and when.

IIRC the removal of the upvote is also federated.
When you change it to a downvote you first need to remove the upvote, that's why it changed from 11 to 9.
So, in instances B and C you'll end up with 10 score.

Keep in mind that not everyone is using the upvotes weighting, so it's not just about "those who allow downvotes and those who don't".

Personally, I find the whole upvoting/downvoting thing to be a very toxic feature that encourages hive mind and blaming divergence, so I hide scores and I sort posts and comments by chronological order. I would not use Lemmy if I was forced to be under the influence of social scoring, so defederating from instances which do not apply the same rules on downvoting would feel very detrimental to me.

Upvotes/downvotes were implemented by websites like Reddit as a scaling trick, so they can get millions of users without the need to hire hundreds of thousands of moderators. But it turned out that adding subreddits with volunteer moderators worked better anyway, and this is already what we have on Lemmy, with instance owners and community moderators, so there is really no need for some dystopian scoring of everything someone says.

Voting doesn't seem to affect visibility very much.

Technically, yes. But you seem to have missed the point of a social network. (Too absorbed by the commercial ones?)

If it mattered at all, the platform would be worthless. There is nothing stopping an instance from just lying about those numbers anyway.

Yes. We should get rid of upvotes too to make it fair.

This is nonsense.

Instances without downvotes can not downvote you. You CAN downvote them from your instance though.

This is clearly about Hexbear. Your downvotes from lemmy.ml work against Hexbear comments, Hexbear users on the other hand are absolutely not downvoting you.

Hexbear is just a very active instance. Up until a couple weeks ago hexbear was 25% of all Lemmy content, and before the reddit waves it was the largest instance.