You're missing the entire argument. The argument here is that they are not pirates, because copyright is stifles the spread of knowledge and should therefore be completely abolished.
Whether you get it or not is something different all together. But that's what people are fighting for.
Where do they discuss the topic ? as much I loved zlib .. I cannot forget that copyrights is what allows knowledge to be spread most of the time. If people couldn't at least live from their writing (not even make a big profit) how else would book emerge ?
Somewhere, a publisher is giggling as they change the constants in problems in an otherwise unchanged first semester physics book with an upcoming new edition.
I think a lot of good books never pay their authors much, at least in proportion to the effort that goes into researching and writing them. Scihub was also violating copyright, but academic paper authors don't get paid by publishers; they the journals. Lots of intellectual labor goes into producing a good where the author would much rather you read it without paying than buy it but not read it.
This is all to say, the publishers, who are perhaps no longer needed in the 21st century, are sales motivated, but there's at least a substantial category of authors who are not.
"It's open because we violated copyright and uploaded it in the open."
Call it what it is. Pirated books. People that must use them still will but at least now we'll know what it is.