Using the quote below, why did some Americans find Malcoms views alarming?

Concerning nonviolence: it is criminal to teach a man not to defend himself when he is the constant victim of brutal attacks.  It is legal and lawful to own a shotgun or a rifle. We believe in obeying the law…. [T}he time has come for the American Negro to fight back in self defense whenever and wherever he is being unjustly and unlawfully attacked. Malcolm X