Robespierre was a Jacobin, a type of radical who wanted to modernize France and get rid of the monarchy. He also wanted to erase all nobility. He wanted to unite the people and figured he could do this by forcing everyone to accept his idea of modernizing France. If people weren't radical enough, they would be put to death. This is definitely not heroic, a typical hero saves lives. Killing innocent people with different opinions isn't virtuous or good for France. The loss of France's people didn't unite them at all.
Robespierre thought that forcing people to remain faithful to the ideas of the revolution would help France. Forcing them to go against their own opinion and killing them if they don't doesn't do any good. If anything he hurt France by decreasing the population and taking away freedom of speech. This man did absolutely nothing to help France or to unite it. All of France was in danger and fearful. Robespierre wanted to eliminate nobility so that everyone would be equal and have more freedom. He didn't give any of France freedom because he forced them to go against what they believe and agree with him. Therefore, he is not a hero. He harmed the people of France; he didn't save them at all.