I understand your frustration, but the point here is famous people versus regular. Not western vs eastern culture (for naming conventions). And I think its ok for famous people to be able to go by their public persona or stage name.
I agree with you that the examples you cited seem to have no remedy. What's your proposed solution?
Not have a real-name policy. Identity is too complex a concept to be reduced to simple data structures, no matter how much us engineers desperately want to.
If one is concerned about impersonation, attack impersonation - impersonation can and will happen even with a strongly-enforced real-name policy (name changes, anyone?). Empower support to deal with impersonation on a case-by-case basis.
Open-endedness in this sort of enforcement can be risky, but it's certainly better than the "baby with the water" policy the way it is right now.
I agree with you that the examples you cited seem to have no remedy. What's your proposed solution?