Actually the correct statement (although they sound almost the same) would be that red cats are rare, and often there are red cats. So the cat had red hair (red color), it should receive two genes for red coat color, one from the mother (red, calico or tortoiseshell) and one from the father (which should be exactly and only red).
The cat should be only one gene for red, which he can get from mother (red, calico or turtle). Inheritance of red hair in cats is associated with such a phenomenon as dominant epistasis (suppression by dominant alleles of one gene of the action of an allelic pair of another gene).
The result of the interaction of the black pigment becomes red and appear red kittens! In the case of cats redhead wool is a good example of the interaction of genes in which one gene alters the result of the actions of another.