Abdominal wounds are the worst injuries to inflict on someone.
I think MattM can attest to this better, but here goes my take.
The most dense amount of tissue is located there, the lengthy large and small intestines are coiled around like a snake.
The painful wound -- bullet, knife, or sword -- penetrates the digestive system spreading bacteria into the blood stream and the rest of the body, which leads to sepsis.
Why shoot someone in the gut to cause a slow, painful death that is difficult to treat?
There's no reason for this, other than sadism.
And ICE can be issued effective non-lethal rounds
Lastly, Araujo could have been picked up at a later date without violence as ICE had all of his pedigree info and he had nowhere to hide.
As retired 73rd Precint NYPD homicide detective First Grade "P.M." -- a good New York Irishman -- related to me last century:
"Meh. We'll pick him up tomorrow. Let's go get some coffee." [Sets fire to his Marlboro and enjoys a drag]
Of course, we started this by taking out their horrible Dear Leader, so why would it surprise us if they returned the favor?