Scihub and Napster are "the same thing", in the sense that both are tools that were created to enable the peer to peer sharing of information, one bypasses the journals middlemen, the other the record labels. Information is meant to be free, anything that tries to stop it is going against the nature of info. The way I see it's like trying to stop entropy, good luck trying to create your perpetual motion machine.
You are then saying Amazon and Ebay are the same as The Silk Road.
They are marketplaces, but from an ethical standpoint they are vastly different.
You cannot stop piracy but a different thing is saying music piracy is legitimate. You are conflating different things.
If you don't understand the difference between Napster and Scihub you probably think music piracy is OK. It is not.
First of all, scholars themselves use Scihub and most scholars that do not have a conflict of interest disagree with how companies like Elsevier operate.
I think music piracy is more than OK, it is good. I also understand the distinction you are trying to make and it is a makes sense. Journals add nothing. Musicians, producers, and other technicians do work to make music.
There is real time and money involved in songwriting, composing, interpreting, recording, marketing, etc.
In this case, the journals paid nothing for the research they publish, and they share none of the money they make.
An analogy for a journal would be a napster that forces you to publish your music there and then doesn't pay you anything.