I would agree with the others, you need to put in a complaint. If the nurse treats all diabetics the same way, how many won't go back and get the help they need, which then can lead to further complications. After a lot of hassle in my local GP surgery, I finally put several complaints in (some they conveniently lost) for loosing records and not following up their own procedures things are slowly improving, (they even made the news for the numbers of complaints people have put in).
If you have a hospital local to you and have a diabetic team, you could express your concerns and ask to be referred to them. I am at this point thinking on this idea myself, but having trouble identifying if they have a good reputation or not.