Teachers like you are not only language teachers but also cultural mediators of the language you teach. That is, unless youi viewed ESL as a mere commodity in corporate education.
Maybe, you would like reflect about your role as teacher and cultural mediator a bit more deeply?

What utter rubbish!

My job is to teach them English and what is and isn't acceptable use of; what words are considered acceptable and what words are considered impolite (for example you may learn the adjective 'ugly' but it is impolite to call somebody that, use instead the adjective 'unattractive'). It is not my job to teach them about England and the culture of the country. If it comes up as part of a discussion that's fine, it's not an off-limits topic, or if it makes sense to have a lesson about England as a way of talking about particular vocabulary (sight-seeing, for instance) then fair enough... but it isn't my job to teach them about the country I'm from, it's my job to teach them how to speak English fluently.

This does not mean I view ESL as a commodity, not does it mean it's anything to do with 'corporate' education... It means I take my role as a language teacher seriously and know that means educating them about the language, not where I happen to have been born.