> tractable syntactic method for proving the absence of certain program behaviors by classifying phrases according to the kinds of values they compute.
Technical books often define terms in a way convenient for the material and approach they are presenting, not in a way that is general to the field; particularly, if terms are used in different ways within the field at the time they are written, they typically have to choose for consistency within the book -- that doesn't make that definition the right one for the field, it simply means that's what the term means in the context of the work.
And, ultimately, the semantic argument is meaningless. It doesn't really matter whether you have static and dynamic types in different languages or you call the former "types" and the latter "tags" (except that the former terminology actually explains the difference in a way that tells you what the difference is every time you use the terms.) The substance is the same, and getting worked up over line-drawing regarding the boundary of "type" is a distraction from any discussion of substance.