I agree that learning a second, third, fourth, etc language is a wonderful thing (I am going to do so myself in the near future) but that concept is a far cry from the idea that the indigenous people of a nation MUST learn another language to get by in daily life, as a result of mass immigration from people from a foreign nation who speak a foreign language.
Further, many people do have the time, money, or even IQ to learn another language- it's not a particularly easy thing to do, especially if you try to do it as an adult, as opposed to starting at an early age.