Baha'i progressive revelation debunked

Up until this point, I think most Baha’is would be in agreement. This seems to be a fairly common understanding of progressive revelation: that while previous manifestations were appropriate for the conditions they spoke to, it is not necessary or even wise to follow all of their commandments indiscriminately here and now. They are not useless or irrelevant, but we have to examine them carefully to decide what still applies to our situation and what does not. Now, what fewer Baha’is would agree to is the claim that this same sort of caution is also required, to a lesser extent, in following the teachings of Baha’u’llah himself. Many Baha’is seem to feel that because Baha’u’llah is the most recent manifestation of God, the one whose teachings are most relevant to our current needs, they can be followed to the letter, without any discrimination whatsoever. This is something I have heard many times among believers. On any issue, big or small, from deciding the age to hold children responsible for crimes to the rules for contracting a marriage, Baha’u’llah’s word is considered decisive. In less than two hundred years, the sacred writings have become what the Torah has been for more than two thousand, an infallible guide to the needs of every person and every community.

-Moral Relativism and the Bahá'í Faith, Brendan Cook (2006)