It is not, in fact, bad that copyright applies to a wider group than publishers, unless you are using "publisher" extremely broadly to apply to "creators".

If "someone gets attacked for posting an image on social media", that rarely means "lawyers came after me because I posted a screenshot of a page from Sandman". It often means that the poster took someone else's art, snipped off the artist's signature, and posted without attribution, and the artist is rightfully angry. Copyright is what enables that artist to continue to eat and make more art. The same goes for music, or software, or movies.

Sure, the system is horribly abused by uneven power structures, as every system in the world is. For music especially, we all know that the takedowns are usually issued by people who have nothing to do with the creation of the protected work, because of the way licensing and rights grants work in that industry. Automated takedown systems (which have to exist because of the scale of online content) also have no reasonable appeal mechanism, and the people making the decisions don't (and can't) make reasonable assessments about fair use and transformative works.

I'm not saying that everyone who participates in piracy is a bad, wicked thief--I absolutely participate in it myself. But copyright is not the villain here; that's just trying to make us feel justified about our actions. Someone made a creative work I enjoyed, and I don't have a moral right to the product of their effort for free.