For the Sake of Heaven?

The Mishna in Pirkei Avot mentions the difference between a disagreement for the sake of Heaven and for personal ego is the dispute between Shammai & Hillel, for the sake of Heaven, and Korach and his congregation for ego.  The difference is that if the dispute is for the sake of Heaven, then they might disagree, but they did not look on their opponents as enemies.  Korach and his congregation looked on their opponents as evil.