It is incumbent upon the Baha'is to refute the arguments of those that have attacked the Baha'i Faith!

"...Those men, however, who, in this Day, have been led to assail, in their inflammatory writings, the tenets of the Cause of God, are to be treated differently. It is incumbent upon all men, each according to his ability, to refute the arguments of those that have attacked the Faith of God. Thus hath it been decreed by Him Who is the All-Powerful, the Almighty.....If any man were to arise to defend, in his writings, the Cause of God against its assailants, such a man, however inconsiderable his share, shall be so honored in the world to come that the Concourse on high would envy his glory. No pen can depict the loftiness of his station, neither can any tongue describe its splendor. For whosoever standeth firm and steadfast in this holy, this glorious, and exalted Revelation, such power shall be given him as to enable him to face and withstand all that is in heaven and on earth. Of this God is Himself a witness."

Gleanings From the Writings of Bahá’u’lláh, Page 346
http://reference.bahai.org/en/t/b/GWB/gwb-154.html