Soy in its true pure natural form is completely ok. But that planet earth does not exist anymore. There are 2 problems with soy today.
First, soy naturally contains phytoestrogen. This mimics the effects of estrogen in the body. Estrogen is the main female hormone. Now, of course, the amounts are miniscule. But thats where the problem is. Today, the vast majority of processed foods contain soy derivatives in one way or another. Therefore the average american who eats junk and processed food every day is ingesting astronomical amounts of soy derivatives and therefore that means he or she is ingesting astronomical amounts of phytoestrogens. Enough to cause a disruption in the endocrine system.
Second, there are no natural soy beans anymore. All the crops come from GMO, genetically modified seeds which as we all know, those forced mutations in the DNA of the seed create catastrophic genetic defects at a cellular level in humans.
As a rule from naturopathic doctors, avoid soy at all costs. A good hint, just by avoiding junk food and processed foods you're saved. Stick to natural raw foods in its entire form, gass fed, organic non gmo when possible.