This is an interesting debate. I strongly believe, from personal experience that it Type 2 can be autoimmune related too. I had very severe glandular fever around 1994 and was about to be hospitalised because of concerns for my liver due to dehydration. 10 years later, within a short space of time I was diagnosed with rheumatoid arthritis and T2. The focus was one addressing RA while T2 was ignored with the usual advice many others have complained about ie the Eatwell Plate.
As for genetics I disagree. I come from a family with over 100 living relatives. My mother was one of 11 children and my father one of 8, all married, had children and now have grandchildren and great grandchildren and everyone is fit and healthy, despite appalling diets drive by a sweet tooth. One aunt was known to always carry sweets in her handbag and occasionally an M & S cooked chicken to offer as gift for anyone she visited! Food features high on their lists of priorities yet I am the only person to be diabetic...........until a 70 year old aunt was diagnosed 2 years ago.
I had good diet, having studied nutrition and raised a family on a healthy diet, with limited sweet treats. None of my 3 (adult) children have inherited a sweet tooth and all follow a healthy diet, one being vegetarian, and a son an exponent of green tea. None carries any excess weight and I feel the cycle has been broken.
I'm convinced my T2 is a result of auto immune deficiency, just as my RA is. I have no other medical conditions. Just 2 which are both autoimmune ones.
As an aside, since following LCHF I've taken myself off all my RA meds, including methotraxate. Apart from a little morning stiffness in the joints, I'm coping, and I hope it is the diet which is addressing both the T2 and RA.