I have never heard anyone say that high glycemic foods raise cortisol. When i googled it the only thing that popped up was from the lady you posted so that right there says something about her info.
In fact the what i repeatedly read from many sources (just just Peat followers) is that carbs and specifically sugar blunts cortisol.
As for PCOS, i dont know much about it but it would seem that elevated insulin levels play a factor. Fructose does not spike insulin the way glucose (and protein) does. I believe a low carb diet with excess protein is very damaging and can raise cortisol, cause insulin resistance and hypothyroid. Replacing some muscle protein with fruit sugar, dairy and gelatin may help.
Heres an article from Danny Roddy on the subject. Polycystic Ovarian Syndrome (PCOS), Or: How You Lost Your Oxidative Machinery — The Danny Roddy Weblog