It's metal, FFS. The only connection metal has ever really had with 'black music' has been a couple of blues licks on a Judas Priest record from 1974. Do you hear any 'black influence' in Slayer or Iron Maiden? I don't, and that's going back thirty years and more.
Contrary to what white middle class music journos steeped in postcolonial guilt would have you believe, black people did not invent music. It existed in Europe and elsewhere for thousands of years before the first spirituals rang on in them ol' cotton fields back home. Would you criticise Beethoven for lack of 'black influence'? Or, more to the point, why don't you criticise Marvin Gaye for lack of 'white influence'? At least old Marvin had a chance, whereas Chuck Berry 45s were scarce in Ludwig's day. Yes, the blues and rock 'n' roll (as well as every other black style) got pilfered by white people, but it was often augmented and changed beyond recognition in the process. See sampling for similar in black music, or indeed the genesis of rock 'n' roll, which borrowed heavily from hillbilly music made by white people.
Just what is a 'black influence' anyway? Is it rhythm? Is it soul? 'Authenticity'? Seems a bit patronising and borderline racist to me, in that it perpetuates lazy, restrictive and ultimately divisive stereotypes.
Hopefully, that's not what you mean.