Reasons for his negativity
1. Genghis Khan's legacy is negative because he did not hesitate to brutally murder millions of innocent people who were completely innocent. He was known as an evil genius and a tyrant who focused on becoming a universal ruler.; He burnt crops, leveled cities, and killed virtually every human being that he encountered which may have seemed constructive for him as a ruler, but was definitely not focused on his empire as a whole.
2, Genghis Kahn did not even treat his own military well and instead turned him into "the most advanced fighting machine which consisted of people who were cold, unfeeling, and mechanical. He gave them a false idol, himself, who seemed perfect, fearless, and brave when in reality he had a huge fear of dogs and died because of an injury falling off a horse. He was not everything he was built up to be, and he used his evil genius tactic to control others.