It looks strange that the practice of reducing or stopping taking Insulin is regarded as an eating disorder. (Insulin is administered by subcutaneous injection. No one eats Insulin.)
Also is strange to call it diabulimia. No one purges Insulin. Reducing or stopping taking their Insulin to lose weight can be a bit more similar to eating very little or missing meals to lose weight (anorexia).
The example of diabulimia is a straightforward example that shows that condition is caused by the pseudoscience of weight gain/weight loss. Not by factors like body image distortion (BID), biological factors, a desire for perfection, rarely being satisfied with what you've done, being very critical of yourself, being overly competitive about things, etc.
Reducing or stopping taking their Insulin to lose weight was the unheard practice before the appearance of the Carbohydrates Insulin Model of Obesity (CIM).
There is only one cause for the practice of reducing or stopping taking Insulin to lose weight, and it is the Carbohydrates Insulin Model of Obesity (CIM). (For eating disorders, professionals are far more comfortable diagnosing mentally ill people who skip Insulin to lose weight than confront the Carbohydrates Insulin Model of Obesity (CIM).)
Without pseudoscience of weight gain/weight loss, there will not be eating disordered caused by an intention to lose weight or by the fear of gaining unwanted weight.