[Beckwith]

I've been wondering why he's still using the title ...

It is custom and tradition to refer to a person by their highest held rank:

Judge Napolitano
General Vallely
Ambassador Wilson
Secret Agent Plame

[AmeriBrit]

I should have said why isn't he referred too as 'Former-Ambassador''Ex' or as Major General Vallely does and use (Ret)after his name and title.

I have a title for him but don't think I'd be allowed to post it here.