I just know that some users changed their names for privacy reasons and probably don't want to be listed there.
Changing your nickname doesn't help anything.
The profile ID remains the same:
For example:
https://bitcointalk.org/index.php?action=profile;u=547435You can hide your identity only by deleting your account. But this function was removed long ago
But even the great Anonymous (first deleted user on bitcointalk) could be identified (former nickname is Immanuel Go/Atlas )