My headcanon is that the whole Jedi code is the way it is because they want young jedi to essentially lobotomize their own morality so that they don't think too hard about the Republic. Maybe some "dark Jedi" in the past had really good reasons to be angry and fight against the republic, but they were smeared posthumously as being "Sith Lords" the same way John Brown gets called a terrorist. It goes well with the culty vibes that the Jedi Order gives off in the Prequel Trilogy.