These people aren't concerned with other cultures and the culture's languages. They just want everyone to be like them. If English is the only language that is allowed to be spoken, the racist will be happy because everyone will be forced to speak English and English only. There will be a big conflict between people who speak different languages and people who only speak English.
If someone is bilingual, the person can help his race to join together with another race. This person can help two different groups with two different languages understand each other. The more bilingualism there is, the more that people that speak different languages will understand each other; thus, people will join together.