donuts is

I’ve been rereading The Cambridge Encyclopedia of the English Language the last few nights. (Yeah, I’m a geek.) For anyone even remotely interested in language, it’s an interesting primer on the language’s evolution over the centuries. (It’s particularly fascinating on dialects — the ways in which, say, New Zealand English differs from Australian English, or how what people speak in Alabama differs from what they speak in Minnesota.)
Anyway, last night I was reading a short section on West Indies English, and how it’s a unique variant in part because the region has both British and American English influences in close proximity. That’s when I noticed this (you can see it here, in the box at page bottom):
“Puerto Rico became part of the USA following the Spanish-American war in 1898. Donuts is one of the consequences.”
The donut reference is to an accompanying photo of “Raul’s Mini Donuts”; the point the author is making is that Puerto Ricans spell the word “donuts” and not the British “doughnuts.”
But: “Donuts is one of the consequences”? Donuts is?
Is this right? It’s a book about the English language, so I presume an editor would have caught it if it’s wrong. And I can understand the way in which “donuts” is being used as a concept, not a number of items. (As in, “The donut is one of the consequences.”) We’re talking about the Platonic ideal of a donut, the ur-donut. Or if the word donuts had been put in quotes, making it a clear reference to the word “Donuts” in the Raul’s sign, I could sign on.
But isn’t it wrong the way it’s written? Or am I showing my American English bias? I know I’ve got some copy-editor readers — hook me up, people.