It's all down to the nitrates used for curing, but the evidence is very shaky, not taking any other part of one's diet into consideration.
My understanding is, as diabetics, it's not food that affects our BG. It's carbohydrates in particular (possibly beens and pulses too a bit). Meat and fat doesn't have an effect.
So we don't have to worry about bacon.
If you're seeing a dietician, they may not be happy over the fat and calories though, cause of weight management. (I had a problem with my diabetic dietician because I had bacon once!) That's a different issue though.