By default, Lemmy allows downvotes globally. However, when a server disables downvoting, it is similar to using a feature that is usually reserved for enterprises and very small, non-federated communities.
If a user prefer to not see downvotes, they can disable it by his favourite client settings, but the rest of the community should not miss this functionality for the pleasure of few users.
Reposting is a huge problem on the NSFW instance, you can see the same picture/video on multiple communities with the same title or a small variation, sometimes it doesn’t even fit the community, but those are the sellers that they were trying to protect… Along with their cringe commenting bots.