Someone could literally make a website listing downvotes throughout the fediverse, and there's nothing stopping them.
This is why I agree that it should be shown upfront. A lot of people won’t like it, but I think users should be somewhat aware that it’s all technically visible.
Someone is gonna make an instance that does exactly this at some point. It will be inevitable as the fediverse matures.
Also, even if they wanted to I don’t think voting could be made anonymous at this point, either. I’m not a programmer in any sense, but I imagine it would totally break federation. Total anonymity would probably need to be a feature from the start.
Kbin at least puts it out there so you know it’s not totally anonymous. Sometimes I wonder how many lemmy users are unaware of this because the software doesn’t make it apparent.