Well, it's not really clear-cut, which is part of my point, but probably the 2 most significant people I could think of would be Babbage and Turing, both of whom were English. Definitely could make arguments about what is or isn't considered a 'computer', to the point where it's fuzzy, but regardless of how you look at it, 'computers were invented in America' is rather a stretch.

I think the author's intended implication is absolutely that it's a dollar because the USA invented the computer. The two problems I have is that:

1. He's talking about the American Standard Code for Information Interchange, not computers at that point
2. Brits or Germans invented the computer (although I can't deny that most of today's commercial computers trace back to the US)

It's just a lazy bit of thinking in an otherwise excellent and internationally-minded article and so it stuck out to me too.