Out of curiosity, why do you think this? Grand theft of wealth based on fraud doesn't strike me as morally worse than gangbanging, armed robbery, human trafficking, etc.
(To detail my own calibration, I would say someone like Henry Kissinger is morally worse than low-level criminals. Typically I think it goes theft < violence < warmongering, etc.)
Someone who is intellectually mediocre, grows up around violent scumbags, and ends up robbing others instead of working a job is reprehensible, but I would say less so than a Bernie Madoff who was already wealthy, highly capable, and decided to defraud people of their life savings over decades. Madoff is not someone like Martin Shkreli bullshitting wealthy investors out of some portion of their wealth, he's someone who ruined people's lives.
People often discount "economic" crimes that they can't directly see the harms of, like insurance fraud, welfare fraud, tax cheating, corruption etc. That's easy to do in places like the US, but becomes more obviously problematic in places like Southern Italy or Argentina whose economies have gradually been destroyed by a widespread acceptance of corruption, cheating and "economic" crimes.