The names Whitethroat and blackthroat, are common names. They are used to identify localized populations or used, in our cases, to identify animals that come into the varanid trade here in the states.
Yours is not a whitethroat or a normal blackthroat. You must remember, monitors do not conform to what you want them to look like. Which means, there is tremendous variation in any givin population. This would include what you consider normal and occasionally odd colors and patterns.
When you get an odd animal, it very well could be one that was dropped off at the exporters by someone from an area not normally collected. Or simply odd for the normal area. This you will never know because there is no locality data.
About albigs, CITES identifys these as V.a.mirostitus and V.a.albigularis. They are subspecies. A subspecies are closely related animals that may only have the slighest differences, like color, pattern, size, or small scalation differences. Subspecies normally intergrade, species normally do not. Subspecies are locality morphs of the same species. For instance, you know, my whitethroats are different then Ionidies blackthroats, don't you. Ionidies blackthroats are from a different locality then my whitethroats. Having subspecies, helps you identify this.
Also, common names, are to help you do this. for instance, an amel gopher, tells you, its not a normal gopher. Thats simply a name to help you identify and converse about a particular individual.
About what some local U.S. boys want to call them, hey, they can call them anything they want. But surely it was of no help to you. The truth is, both scientific nomenclature(sp) and common names are suppose to be of use. That is, they are suppose to be helpful. If they want to muck around and make them of no use, then you have to consider that they may be very poor at their job. The reason for naming them, is to give you an understanding, that is all. Good luck F