Ask them if they really believe in 'making disciples of all nations", the passage where Jesus gives his followers the command to go, make disciples from all ethnic groups (not just Israel), baptize them, and teach them to obey everything he commanded,
promising his presence with them until the end of the age. Then ask them, "Isn't it convenient they come to you and you don't have to be a missionary in their country?" Then ask, "Can a brown-skinned Indian person be converted and become an ambassador for Christ?"