In short, the forensic accounting for FTX claims they have adequate evidence they were complicit, and they've been sued for such, so far.
But, to your point, that's rather vague.
There is quite a difference between murdering someone, and stealing a bunch of peoples money to the justice system. I am not saying that makes sense, but it's really hard to judge a crime when the year count starts getting into 10+ years. Would you be happy if it is 5x lifetime? Or some other silly number that means nothing?
Where I would put my energy into is making the risk of being prosecuted higher. If getting prosecuted is rare, the kind of people who are into cryptocurrency are going to figure that they’re likely to get away with it as long as they aren’t so blatant. White collar crime prevention needs to focus on changing that assumption.
Your parent post isn’t arguing for SBF to get 30 years, but pointing out how a large crime which affected at least hundreds of thousands and drove people to suicide gets a lower sentence than a violent crime which affects one person.
I have no idea if that’s true in the US, just trying to clarify the point.