"The fundamental purpose animating the Faith of God and His Religion is to safeguard the interests and promote the unity of the human race, and to foster the spirit of love and fellowship amongst men." He warns, "Suffer it not to become a source of dissension and discord, of hate and enmity." - Gleanings from the Writings of Bahá'u'lláh, p. 215 [By 'Faith of God and His Religion' is meant all the past as well as the future religious dispensations, because the Bahá'í teachings assert there is only one God and one religion revealed by successive Teachers over time.]
The purpose of the Bahá'í Faith, which its followers believe to be the latest chapter in God's ongoing religious guidance, is this: "In its affirmation of the validity of the great religions of the past, the Kitáb-i-Aqdas [Book of Laws] reiterates those eternal truths enunciated by all the Divine Messengers: the unity of God, love of one's neighbour, and the moral purpose of earthly life. At the same time it removes those elements of past religious codes that now constitute obstacles to the emerging unification of the world and the reconstruction of human society." - Bahá'u'lláh, Kitáb-i-Aqdas, p. 2
'Abdu'l-Bahá, the son of Bahá'u'lláh, in a treatise to ecclesiastics on the purpose of religion, explains:
"There are two kinds of civilization--material civilization which serves the physical world and divine civilization which renders service to the world of morality. The founders of the material, practical civilization are the scientists and investigators and the establishers of divine civilization are the celestial universal teachers.
"True religion is the basis of divine civilization. Material civilization is like unto the body; divine civilization is like unto the spirit. A body without the spirit is dead, although it may be clothed in the utmost beauty and comeliness.
"In short, by religion we mean those necessary bonds which have power to unify. This has ever been the essence of the religion of God.... Alas! A thousand times alas! that this solid foundation is abandoned and forgotten and the leaders of religions have fabricated a set of superstitions and rituals which are at complete variance with the underlying thought. As these man-made ideas differ from each other they cause dissension which breeds strife and ends in war and bloodshed; the blood of innocent people is spilled, their possessions are pillaged and their children become captives and orphans....
"Thus religion which was destined to become the cause of friendship has become the cause of enmity. Religion, which was meant to be sweet honey, is changed into bitter poison. Religion, the function of which was to illumine humanity, has become the factor of obscuration and gloom. Religion, which was to confer the consciousness of everlasting life, has become the fiendish instrument of death. As long as these superstitions are in the hands and these nets of dissimulation and hypocrisy in the fingers, religion will be the most harmful agency on this planet. These superannuated traditions, which are inherited unto the present day, must be abandoned, and thus free from past superstitions we must investigate the original intention." - Divine Philosophy, pp. 160-161
If I accept that the purpose of religion is the unification of the entire human race, and that any movement--religious or otherwise--which facilitates unity is also in line with divine intention, then deciding how to live my life is easier. I can choose not to support factions which cause separation and disunity, no matter how attractive their mission statements. Because as a follower of Bahá'u'lláh I believe that all humanity is one family, whom I regard as my own, I will be less likely to pursue personal goals that will cause harm.
That said, I admit family members frequently misbehave, but that doesn't free me to do the same. Only faith keeps me focused and pursuing a peaceable world when faced with the outrageously ignorant behavior and downright venal intentions of some people.
That is what religion does for mankind: it gives the strength to persist in altruism. Historically, it is the only source of such strength over time and across generations.