giving the wind human characteristics and actions helps the reader to visualize the ferocity and anger in the wind.
when people are vicious and angry they seem much more powerful
by saying that "and said that he'd kill and kill...And so he will and so he will" seems to me to stand for the dangerous, easily vicious, and easily swayed nature that the enraged man and wind might share.
He compares the wind of a natural disaster such as a tornadoe to man, and man's emotions
He compares the wind and human characteristics and actions helps the reader to visualize the ferocity and anger in the wind.