Your quote is lifted from an anti-Baha'i website which contains a translation of something Baha'u'llah has said, as translated by the Muslim divines with the additional words highlited being added by them which do not appear in the original text
Interesting. Then care to tell me this? (I just randomly stumbled on this):
“The inhabitants of a country life Africa are all as wandering
savages and wild animals. They lack intelligence and knowledge; all are
uncivilized; not one civilized and a wise man is not to be found among
them. These are the proofs of the wise men. The prophets also
acknowledge this opinion, towit: That education hath a great effect
upon the human race, but they declare that minds and comprehensions are
originally different. And this matter is self-evident; it cannot be
refuted. We see that certain children of the same age, nativity and
race, nay, from the same household, under the tutorship of one teacher,
differ in their minds and conprehensions. One advanceth rapidly,
another is slow in catching the rays of culture, still another
remaineth in the lowest degree of stupidity. No matter how much the
shell is educated (or polished), it can never become a radiant pearl.
The black stone will not become the world-illumined gem.” (Tablets of
‘Abdu’l-Baha p.567 vv.3-4)