I believe the way they deal with this is by having the recipient create a one-time address for every sender, so it is not possible to recognize patterns between senders and recipients. Another thing is that every wallet has two associated keys. There is a “spend key”, which is a write-only key that can spend money from the wallet, and a “view key”, which can be used to view the contents of the wallet. You can publish the view key if you want that to be public information, but you don’t have to.