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.
I mean that what you call “the solution” (to curate one’s feed) already exists and did not solve the problem for the platform as a whole, as attested by the OP. Because regardless of what you or me think that people “should” do, they’re still browsing by “All” (that’s fine) and then downvoting content geared towards other audiences (that is not fine).
And it is not just porn; you see the exact same issue with content in other languages. Same deal: the resource exists (you can set up the language of your content, as well as the ones that you want to see) and people still don’t use it.
You’re suggesting that people should make use of that resource, but our suggestions mean nothing if people won’t follow them. We do need a way to at least encourage the usage of those resources, and discourage this idiotic “this content is not made for ME! ME! ME!, how do they dare? Downvoting time!” tendency.
It might not solve the problem but it does alleviate it. There’s a big difference between seeing 10% or 50% of irrelevant content.
But tags have the exact same issue as the current solution, which is that someone has to set up what tags the user wants to see and the only one who can set them up is the user itself. The current solution already does a better job at solving the problem than tags would and people don’t use it. If the people don’t use the current solution why would they use tags? Why not just improve the current solution so people would use it?