Privacy issues

Being able to prevent players who aren't logged in from seeing your page is helpful in preventing people you have blacklisted from stalking you, but this has gone too far.

Not being able to search someone up is extremely disruptive to the raiding scene and makes it harder to bring public awareness about known botters or griefers to newer players/reporting them for their actions.

One common reason for players to have their page private is because they used a paid third party program to obtain the Accursed Hoard in Deep Dungeons (Usually Heaven on High) at a rate more than twice of what is reasonably humanly possible without addons for periods of time considerably longer than any human would be able to stay awake at a computer for.

Another common reason is not wanting other players to know that they're "Paypal Legends", people who have paid RMT sites over a hundred euros (And handed over their account details) in most cases to get a clear of an Ultimate Raid. The easiest way to tell if someone is one is if their clear and unlock date for the Ultimate is on the same day, but with hidden achievements, no-one can call you out on that or report the account for RMT with that undeniable evidence.