No, this is EXACTLY the point. Dr. Unwin from the UK gave this presentation.
His point was that the huge spike produced a much bigger AUC (area under the curve).
And that the slower digested food tends to produce a single insulin spike, unless you keep eating. (so, as long as the glucose is not really high, and you stop eating, you usually wont get the second hit of insulin)
Which, FWIW, is why drinking sweet (diet) sodas long after a meal is detrimental for many.
The body mistakes this for nutrition, and keeps spitting out insulin, which blocks your access to stored energy.