D'Enghien was in the pay of the British government (4,200 guineas a year) when France was at war. He was convicted by a court-martial of being guilty of violating Article 2 of the Law of 6 October 1791: to wit-'Any conspiracy and plot aimed at disturbing the State by civil war, and arming the citizens against one another, or against lawful authority, will be punished by death.' D'Enghien was a French citizen and stated at his court-martial: 'I asked England if I might serve in her armies, but she replied that that was impossible: I must wait on the Rhine, where I would have a part to play immediately, and I was in fact waiting.'
Andreas Hofer was a leader of the rebellions in the Tyrol against the Bavarians who were now (1809) sovereign over the Tyrol. When Austria was defeated, Hofer surrendered and was granted amnesty, but again took up arms later and was betrayed to the Bavarians and the French and was court-martialed and executed.
If you condemn these actions, then you must in all fairness condemn the assassination plots against Napoleon who was the legitimate head of state of France. And in the Rue Saint-Nicaise plot and the explosion of the bomb designed to murder Napoleon. Entire houses were demolished in the explosion and the little girl the plotters asked to hold the horse with the cart with the bomb was vaporized. In all nine innocent people were killed and twenty-six were wounded. That was murder. The executions of d'Enghien and Hofer were not.
I have not read anything that you have written condemning the British-supported Bourbon murder plots against Napoleon, or Georges Cadoudal's actions in those plots. He too was caught and executed, rightly so.
It's called law and order and judging them by early 21st century standards is ridiculous. In many ways justice in early 19th century Europe, Britain included, was of the 24-hour variety of taking the guilty party, trying him, finding him guilty, and then either imprisoning him or executing him, depending on the severity of the crime. Legal 'niceties' were not part of the equation. And murdering innocent bystanders, for which the Bourbons and British government both planned and condoned, was definitely outside the Pale. Cadoudal, d'Enghien, and Hofer were guilty. like it or not. The execution of d'Enghien outraged the courts of Europe because he was of royal blood, not because he was innocent.