Why was Abame massacred in Things Fall Apart?

Abame was massacred in revenge for the killing of a white man on an iron horse.

Abame was foolish for killing a man who said nothing.

The men of Abame, being foretold that white men would bring doom to their village, foolishly killed a white man and his horse, tying the horse to a tree.

In response, three white men and a very large numbers of other men surrounded the market, then opened fire. Everybody at the market place was killed except the old and the sick who were at home and a handful of men and women whose chi were wide awake and brought to the market.