I think the main problem is how they test it - what first shows ketones is a urine dip stick, although it's usually associated with other symptoms, such as urinary frequency, thirst, diarrhea, stomach pain, vomiting - it could be a stomach bug, but combined with the presence of urinary ketones, it looks like ketoacidosis.

Most nurses have probably never even heard of nutritional ketosis, so the automatic assumption is that they have a case of ketoacidosis on their hands - whether the patient is diagnosed as diabetic or not. Since ketoacidosis is a very serious life threatening condition it needs to be treated immediately.

One of the first things they do is to give insulin - if someone already has low blood sugars, but high ketones due to nutritional ketoacidosis, that in itself could be life threatening.

So part of the problem is that far too few medical staff even realize there's such a thing as nutritional ketosis. And even if they do - the first line of treatment is still to treat it as if it's ketoacidosis. (Because it's pretty common for diabetics to consume excess carbs - they aren't like to admit it as long as they get away with it either.