I agree with just about everything he says here, especially his emphasis on the challenges of excess protein to the kidney and liver.
People with diabetes absolutely need to limit their protein intake. They suffer microvascular complications in small vessels in the kidney which makes filtering of nitrogenous waste from dietary protein difficult. The deamination, or removal of that nitrogen from protein, takes place in the liver, so a compromised liver (e.g. fatty liver which is also associated with diabetes, cirrhosis, hepatitis ) will also make removal of nitrogen waste difficult.
He addresses soy in the end. Great distinction between whole soy and processed soy derivatives.