Why was Booker described as a whirlwind and why was his speech described as electrifying?

This is referring to the speech that Booker gave in Atlanta. Mr. James Creelman, the noted war correspondent, said that Booker electrified his audience whose responce sounded like it came from a "whirlwind." He felt that no other Nego, "Could have pleaded a cause with more consummate power than did this angular Negro standing in the a nimbus of sunshine, surrounded by men who once fought to keep his race in bondage.”