While I think the customer had a valid point, however she lost my sympathy because of her abusive manner.
There's never anything valid for being a racist!
When my sister and me talk infront English people, we speak english out of politeness and its correct thing to do. However, when we talk to our parents, we revert back to cantonese because my parents English are very poor. So it could be so in this case! And whatever its the reason, there's no need to go on a racisit rant!
Furthermore, this happened in Canada, a country in part speaks French! Will this woman start demanding the French speakers to speak English?!
And what would the response from the general public if that did happen!