Good luck finding every single penny of money that person defrauded to take back, also good luck on preventing that outside of jail he don't use his network to still benefit old acquaintances and indirectly receive enough "help" that he lives a comfortable life outside of jail even doing "community work".
There isn't many things more violent than robbing trillion dollars from taxpayers and through very inneficient healthcare, security and others see thousand people die. That is much more violent than shooting someone.
Do you really believe that someone who's just been sentenced for financial crimes and lost all of his possessions will just go out and do major crimes again? Do you believe his associates will still associate with someone who's monitored? If you believe that a person cannot stop doing crimes even after they've been sentenced you might as well just kill them. No amount of prison time will change that person.
The problems you are describing are rooted in the system and not single individuals. Capturing them and throwing them in jail won't help anyone and be nothing more than a drag on society. Kill them or set them free, prison is a no-win game.
If you demand respect or gratitude for your volunteer work, you're doing volunteering wrong.