You are missing the point. Many (not all, but many) of guys with PFS have altered receptor function/altered hormones. Therefore, what applies to most guys no longer applies to us. That is why for normal guys soy is probably not very good, but paradoxically for PFS guys soy may be helpful for us.
Also to reiterate, the primary issue regarding soy is not estrogen, nor is it productive to get caught up in the whole soy = estrogen debate; while this is true to an extent, what is more important to consider is that soy downregulates the androgen receptors themselves. This in itself is huge, and extremely important. So basically with regards to soy, its not a black and white issue, soy needs to be considered on a couple of different levels because its mechanism through it affects guys with PFS is deeper and potentially more complex than what most people think.