You should re-enrol in Reading Comprehension 101, Chris89 ...  

Yes, blues is a product of American culture ...  (it is more accurate to say it is an end product of slavery, but never mind that.)

My point is the criticism being levelled against British blues players is a crock ... guys like John Mayall and Alexis Korner brought blues back to prominence, not Paul Butterfield and Les Paul ...

Without the Beatles, Stones and Cream and, later, Led Zeppelin, you would have never even heard of Willie Dixon (or Paul Butterfield.)