Can a doctor, chiropractor, or therapist obtain a garnishment judgement against a former patient for money owed? Sure. ANYBODY you owe money to can pursue a court-ordered garnishment.
Can a hospital garnish wages for unpaid bills? Yes.
I was told that doctor, chiropractor, therapist, or hospital garnishment claims "would not stand up in court." Is this a true statement? Whoever told you that is full of hooey. A medical provider has the same right to pursue bad debts as does any other business entity. Why wouldn't they???
A person, who is nice to you, but rude to a waiter, is not a nice person. (This is very important. Pay attention. It never fails.)