Robespierre is known as the "Incorruptible Man" mainly because of his firm ideals, ambitions and revolutionary style.

Robespierre was an important figure during the French Revolution. He actively promoted the revolutionary process, led the French people to smash the armed intervention of European monarchies, and suppressed the Girondin counter-revolutionary rebellion. He took a series of radical measures, such as implementing terror policies and imposing price limits on the bourgeoisie. Although these measures were designed to attack the enemy, they also aroused popular resistance.

Despite this, Robespierre's position in the French Revolution remains unshakable. He was called the "incorruptible man", reflecting his firm stance among the revolutionaries and his status in the hearts of the people.

However, in 1794, the Thermidorians launched a coup, arrested Robespierre, and executed him. This was mainly because in the process of leading the revolution, Robespierre brutally suppressed both the left and right factions of the Jacobins in order to balance the power within the party. This approach caused backlash and dissatisfaction. At the same time, his radical policies also caused social unrest and dissatisfaction. After the Thermidorian coup, Robespierre was arrested and executed.

In general, Robespierre is called the "Incorruptible Man" mainly because of his firm revolutionary stance and his contribution to the advancement of the French Revolution. However, his ruling methods were too radical and cruel, which aroused social dissatisfaction and resistance, ultimately leading to his tragic ending.