And if you study Japan's immigration/citizenship/settlement policies you'll see just how strict they are.
In Malaysia and Indonesia. Islam is a thorn in Burma’s ribs and Thailand’s foot. When one of these two reacts to Moslem destruction of Buddhist villages or murders of officials and monks they incur the wrath of Western elites and media. Việt Nam does not allow Moslems into the country except as carefully monitored businessmen and diplomats lest they affect VN’s own tiny indigenous Moslem population which is syncretic with local paganism as Indonesia’s Islam was until the Wahhabis and the Brotherhood moved in and took over all the mosques.