Private feedback doesn't bother me, at least in the sense that I often trade with people where I can't check any information like FB can provide... But therein lies the point, a feedback profile contains information, and when people hide information, some people start wondering why.
Just to throw a different perspective out there, every now and then, something prompts me to check a buyer's FB left for others - it can be much more telling than FB received (a serial neg leaver becomes plain to see, or maybe there's a lot of positives with "thanks for the refund" kind of comments). Sellers will often follow up on FB they've left for a buyer (eg chargeback initiated 3 weeks after payment, refunded on x date due to not received), and this can also highlight certain patterns. I'm not in any way suggesting a member with private FB has things like that to hide, as I'm well aware of many different reasons someone might have for keeping FB private. What somebody buys is none of my business etc....but at the same time, as long as eBay facilitates a reflection of someone's trading reputation, there will be people who believe that their trading partner's reputation (which they contribute to by what FB they leave, even if it's none) is their business.
