I agree with KCThy that these are not of much consequence in the grand scheme of things. The ONLY documented cases (as in, published in medical journals) of goitrogenic foods causing problems have occurred in areas of the world where iodine deficiency is rampant and people's diet consists almost solely of a single goitrogenic food (generally millet or cassava.)
These foods exacerabte an existing iodine deficiency. But this is only if you are deficient already, and only if you have a an extremely limited diet and basically eat nothing but goitrogens.
Get sufficient iodine in your diet, and don't worry about goitrogens. There are many extremely beneficial foods in these "lists" and I hate seeing people avoid them for no reason at all.
An analogy might be eggs ... raw egg whites contain a substance called avidin, which binds to biotin (a B vitamin.) If you routinely eat enormous quantities of raw eggs, you can theoretically end up with a biotin deficiency. Biotin deficiency can cause dandruff and dry skin, among other things. Imagine if everyone with dandruff and dry skin decided that they absolutely had to avoid every trace of eggs, and if they took one bite of let's say, a muffin, the next day they would be overwhelmed with horrible dandruff.
Just my opinion of course
If you feel better not eating them, then go ahead ... I just feel like this whole hoo-hah over goitrogens has been severely blown out of proportion. Kind of a pet peeve of mine. I'll step out now...