Teaching a different variety of English in an English-speaking country

I was wondering what everyone here thought of the phenomenon of language schools teaching a different form of English than the one spoken in the country in which the school is located. I welcome comments from other teachers as well as students.

I teach in a U.S.-based private language school in Boston, and all our teachers are, if not native speakers, at least speakers of American English. This is what we teach our students, since, you know, we're in America and all. Recently, we began sharing space with a Canadian school opening their first U.S. campus. Their teachers are mostly American, but the curriculum is dictated by the school, and I've seen what they're teaching, and it's not American English. Now, if I were a student studying in the U.S., and I discovered that what I was learning was not American English but Canadian, British, Australian, or South African English, I'd be pretty upset. Granted, most native speakers can understand Canadians/Brits/Australians/South Africans just fine, but why not use American English textbooks and lesson plans? Are they just ignorant of the differences? Or are they being snobs?

It's not limited to this school, either. I'm planning a cross-country move, so I've been scoping out jobs. I came across one school's website with bios on their teachers, all of whom were American, and all of whom were writing in British English! Or, more likely, they wrote their bios in American English, since they were all American-born, and the (Britain-based) school edited them. That, to me, is just unconscionable.

What do you think? Is it fair for an English-language school to teach the variety of English spoken in the country in which it is based, even as it expands overseas? Should they at least disclose this upfront ("We are based in -----------, and teach ---------ian English")? Or is what they are doing fundamentally dishonest?

ETA: Here's an example of what I'm talking about:

My experience:

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Born and raised in Southern California, I hail from the exquisite town of Riverside, California. I graduated from UC Santa Barbara with Honours, acquiring a degree in Linguistics and Global Studies. I spent my junior year abroad in France, which really roused my interest in international education.
After some teaching and an internship with Embassy, I was honoured to become Student Services Representative. Though absorbed in my position, I still find time to practise piano, play tennis, teach dance, perform in musical theatre, and paint

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Er, no. You did not graduate from UC Santa Barbara with "honours;" I have it on good authority that school only graduates students with "honors." And if you were born and raised in California, and live and work there still, I doubt you "practise" piano; you probably just "practice" it. I could go on, but I'm sure you get the picture.

I don't know whether it's snobbery, but it does make sense to teach AmE in the US, and so on, without excluding contact with the variants. Maybe as schools expand, they prefer to stick to the methods, materials, etc, that they already have, but I don't think this is a good idea if it is the case.

The piece you quoted reads so artificially to me that I wonder whether someone wrote it from notes - the repetition of California in the first sentence, for instance - rather than the teacher.