There are proposed diabetic mechanisms which are exacerbated by cholesterol. Plant based food are completely devoid of cholesterol and have dramatically lower incidences of diabetes. So there you have a mechanism, and the demonstrable effect of abstaining from that source of food. What else do you want?
https://diabetesjournals.org/diabetes/article/56/9/2328/1265...
https://www.mdpi.com/2218-273X/13/2/224