It’s called xenophobia, the fear and dislike of anything foreign. Some people believe that if your group isn’t dominant it will be dominated, and peaceful coexistence isn’t possible between different groups.
These people are afraid that, if the English language isn’t forced onto other people, one day other people will force a foreign language onto them.
The producer said he was speaking only for himself personally and not for the company, so my guess is that he personally liked Kojima and wasn’t involved in kicking him out. The Konami CEO and executives probably don’t share the same dream as this producer.