Like in most shidduch cases, a girl with diabetes is in a different boat than a boy with diabetes.
It is so hard for any girl to get dates nowadays, I can only imagine how much harder it is for girls with diabetes.
On the other hand, boys usually have lists as tall as them (actually probably taller, since I find that frum boys are usually pretty short!) A boy with diabtetes may just have a shorter list, but I am sure they still get dates.