My W doesn't have the name problem.
It would seem to me, that they don't know who they are, and so they have trouble saying who you are.
Are you their spouse? or maybe ex-spouse? maybe Satan? or what?
So, they just avoid it.. and when it comes up.. they don't even know what to say, b/c they really aren't sure.
I don't think it's an insult, I think they just really don't know.
"Hey you! You can't even dig a ditch, can ya?"