That's a bit of an exaggeration. The Black Panthers were at least founded for self-defense, whereas the KKK was initially and exclusively devoted to provocative and instigative racial aggression. Building upon that, though their militant tactics have been sensationalized, the Black Panthers have had purposes other than such militancy, whereas the KKK have effectively not. The Black Panthers also tolerated a significant amount of ideological diversity (having members that were either exclusively socialists or black nationalists in many cases), that the KKK has traditionally had no place for.
That is not an exaggeration in the least. The New Black Panther party is as bit of racist, violent, anti-government and as dangerous as the KKK.
You say they were founded on self-defense! LOL, the Black Panthers started out as a motor-cycle gang! The Crypts and the Bloods, MS-13, Aryan Nation, Latin Kings, Eme etc were all founded on self-defense, as you going to stick up for these "organizations?" The Black Panthers do nothing positive and they only hurt America not help her.
Also note that the original KKK was set up, as they stated, for PROTECTION against the crazy "negros," Jews, Catholics, Indians, Mexicans etc!