I'm not offended if someone calls me that, no.
By the same token, should white people not be offended by terms such as "******" or "paki" then?
I'm not offended if someone calls me that, no.
Quite obviously not.
Would a black person be offended if someone called them a white bastard?
I think the point Edna was making was not that a white person would be personally offended by these terms, but would find the use of the words offensive.