He was judged before a jury of his peers and found wanting. It's not revenge, it's being held accountable for his actions. Some crimes, like murder, can't just be "corrected". The solution we've landed on as a society is for there to be a punitive cost to be paid by the responsible individual. In this case, it's jail time.

SBF caused an incredible amount of irreparable harm with his actions, which almost certainly has resulted in suicides. He deserves this punishment.