Those accounts are run by fans and friends, it is just so that youtube does not delete any uploads citing copyright infringement, for instance, if I upload something by JB Mpiana on youtube with my account as DJ SLY, youtube can remove the file without notice if they have copyright protection issues logged in by SOCODA or directly by a named musician or his/her official representative but if I create an account as JB Mpiana and then upload music wby JB Mpiana, youtube will less likely delete my files as they would believe it's my content or work so no infringement.