In some areas of the Gulf, you can't tell whether you are in an Arab Muslim country or in an Asian district. We can't call this diversity and no nation on earth could accept the erosion of its culture on its own land.
I can't fault the Bahraini minister for acting to conserve his own culture. However, the situation in the Gulf does raise some further questions.
For instance, if the Bahraini minister believes that non-Muslims cannot adapt or assimilate to an Arab Muslim culture, then the same difficulty of assimilation must also occur when Arab Muslims seek residence in foreign countries. If mutual adaptation or assimilation isn't possible in Bahrain, then why would it be possible in France or Finland?
Also, if the Gulf states are so dependent on foreign labour (there are currently 14 million foreign workers in the Gulf), and if this labour force is thought to be too foreign to assimilate or adapt, then why are Middle Eastern refugees being sent to all the way to the West rather than to the nearby Gulf states? The Gulf states are very wealthy and are very much in need of a more assimilable labour force. It would seem to be a good match.