Harrison may be a hero to some and may not be to others because everyone has a different point of view and witness the situation from different positions. However, in my point of view, he is a hero because he had an effort, was brave, and his goal was heroic. In most societies what he did would make him a hero.
In the story, all people were facing the same law. They (including George and Hazel) had an instinct that it was wrong, but no one was willing to break out of it. However, Harrison did it. Even though the result was not successful, at least he tried. I personally think that putting into action is more important than just thinking of it. Therefore, his effort is worthy of being a hero.
Also, most of the goal of a hero is to save people