Which is worse "*****" or "cracka" when referring to black or white people, respectively?

Its seems that it is more socially acceptable for someone (anyone) to say the word "cracker" than it is to say the word "******". Why is that? Shouldn't they both be equally derrogitory? I feel they NEITHER should be used, but I am boggled by the fact that TV/Radio never "beeps out" the word "cracker" and never fails to when the word "******" is used. To make my point YAHOO has even blanked out the word -n-i-g-g-e-r-. in my dialogue above and DID NOT blank out the word cracker. So my point has been well proven, even in just the simple act of posting this question.