I wasn't aware of this. And to be fair to me it seems a bit silly. Preserving a culture is one thing, denying a person the right of choice and the desire to improve upon themselves however is borderline despotism. I am not a native English speaker myself, but I was able to attend an English school. That by no means destroyed my national identity even considering the fact that we had to study 99% of the subjects in English including for example Bulgarian history.
True the language is one of the main things that define the term culture, but knowing more than one doesn't mean you will stop using your native one, and the reason for this is quite simple. Every culture tailors its language or dialect specifically for itself. No one from England for example can express what they 'feel' better in German than in English, same goes for every other country. If you take out the nationality factor from every language you will find out that structurally all of the different forms of communication are fundamentally the same because they express things that are inherently human