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.
People don’t browse only by “subscribed”, nor they know magically all communities with their desired content. As such no, the net effect is not zero because the downvotes still affect the visibility of the whole community, reducing its discoverability and of the content within it.
That’s likely a bug, and irrelevant in this discussion.
True but irrelevant. Specially because what I’m saying does not apply just to porn, it applies to every bloody type of original content, SFW or not. And we definitively do not need reasons to discourage OC production here.