you should be able to click on the small icon image in the activity stream item. i just verified that i can. if you can't, let me know what browser you are using.
you are mostly right about the payer being hidden. i wouldn't go so far as to say it isn't public info, though. the reason the payer is hidden is because in most contexts on the site, it's not useful information. however, since others would need that information to audit the system, it is not considered private information between the two counterparties.