The isoflavones of soy, predominantly genistein and daidzein, are the estrogenic and goitrogenic toxins we are concerned about, and they exist in the unprocessed soybean attached to sugars. We can only absorb the sugar-free form, and there is very little sugar-cutting activity in our intestines able to render these nasties absorbable. Traditional fermentation, however, successfully frees many of these substances from their attached sugars and renders them more absorbable.
Fermentation does lots of good things too, like break down the phytate and produce vitamin K2. Excess iodine appears to protect against the goitrogenic effect of soy, but exactly how protective it is and at what range of soy intakes is still left to the unknown. Therefore, soy should be consumed in moderation as well as with plenty of iodine.
Here is Sarah's blog post on the matter:
Here's the link to my Special Report, the most pertinent information from which Sara nicely summarized:
Honey post is coming. Sorry for the delay!