Why do you think schadenfreude is a negative personality trait or a personality disorder? It is just a name for a specific emotional state. It seems perfectly apt here.
Schadenfreude is when you take satisfaction in someone else's misfortune. I think what the parent comment is saying here is that many of those who are satisfied with the Theranos outcomes aren't satisfied because they take delight in the leaderships' misfortunes; they're satisfied because they take delight in finding out they were right, that they weren't crazy to think that the promises of Theranos didn't make sense, and that there are consequences to the kind of fraud that seems to get some people ahead.
It means taking joy in someone else's suffering, which is basically sadism. I don't see that as being the same thing as being happy to see the truth come out and justice finally happen.
I don't think justice and schadenfreude are terribly different.
Schadenfreude is taking joy in someone else's suffering.
Justice is taking joy in the meting out of suffering to people who deserve it. People argue about who deserves what, and laws and justice systems exist to manage those arguments. But the idea of righteous retribution for a wrong is pretty close to universal, and looks like schadenfreude to me.
Well, in my mind, retribution and justice aren't closely related. Taking revenge on wrongdoers and making things right are not inherently the same thing. I can think of lots of situations where taking revenge on the wrongdoer in no way makes anything right.
