According to my quick Google search, there are about 100 million people in Vietnam. The average wage is $150 per month. $12.5B shared among each person is $125.
Why not make her pay that amount instead of a death sentence?
That's actually what their "death penalty" is trying to do. Apparently most of the money she stole is in overseas bank accounts and relies on her taking action to actually give it back. She has appeals and if she paid up the appeals will probably back down from the death penalty.
Well then. Murdering someone as ex-post "punishment" for past actions remains abhorrent, but holding a gun to her head until she gives the money back is cool and good.
There is a difference between threatening violence as a deterrent against currently engaged in harms a person has the ability to cease and claiming moral authority to end a person's life due to things they have no control over.
There's distinction between "Put down the box or we'll shoot you." and "Having touched the box in the past, you now need to die regardless."
Still don't fuck with "The death penalty" as a framework for the threat, however.