This is so typically American...
If somebody else beat you to an invention, you just ignore it so you can keep your self-centered world view.
An author form any other country would at least have given honourable mention to developments in other countries.
The British colossus was a bigger achievement in my eyes, than the ABC. Moreover, ignoring the first real computer by todays definition (Turing completeness), the Zuse Z3, is hardly understandable, except in a borderline nationalistic context.
I fully acknowledge that the development of computers in the 20th century was mostly an American thing, but history has no room for patriotism.