If the Twitter account provided links to Sci-Hub’s website, it’d be very easy for the journals to construe infringement. Whether the account actually did, I don’t know. I’m just pointing out how it could work.
They could have at least tried to fight it.
They could’ve. But just because they didn’t, doesn’t mean they’re complicit. Someone else mentioned Jim Crow laws as an example of unjust laws that should’ve been fought against. That doesn’t mean everyone who didn’t fight is complicit. If you don’t have the willpower or firepower (legal arguments) to fight something, that doesn’t make you bad for backing out.