Not to mention humans 150 years ago who ate plenty of bread and still didn't have the problems we have with obesity and diabetes. Or even 50 years ago...
A diagnosis today that is imminently manageable like asthma was far more readily in a world without antibiotics, steroids, or even medical oxygen.
Even something like a CPAP that many of us take for granted has only been readily available for 30 years or so.
Plus, diabetes is much like AIDS in that it’s more of a systemic thing than acute. It doesn’t really have symptoms that kill you. It just slowly weakens your body until your heart gives in, or you have a serious infection, or something like that. No one dies “of” diabetes, they die with it.
However, this study seems to compare freshly baked bread to a frozen/toasted one.
I'd guess that the difference will be smaller when regular store-bought bread is used instead.