Answer:
He called her "genuine American hero" because she fought for freedom and justice, just as the great American heroes did.
Step-by-step explanation:
Obama highlights how Rosa Parks questioned the unfair situation she was subjected to and worked to promote social changes that would prevent situations like this from continuing to happen. Rosa defied injustice and this brought about a change not only in the US, but worldwide. Like the great American heroes, Rosa sought and promoted social justice and freedom for the entire black population, as Obama himself said in his speech "And in a single moment, with the simplest of gestures, she helped change America - and change the world. "