The jedi aren't easily manipulated. Even though the entire republic was under the control of Palps, the Jedi's were not. They saw things the way they actually were. An evil leader has manipulated and decieved his way into power, and they had to do what was necessary to make things right. The Jedi's knew that if Palps was to stay in power, countless millions and probably billions of people around the galaxy are going to die. Were they wrong? NO !!! palps kept his power didn't he, and how many people died because of it? Entire planets were destroyed in seconds with the death star.
Use your brain dude. The Jedi's ABSOLUTELY did the right thing, even though Mace did not. Every lie that palps told Anakin in the movie to turn him to the dark side, you believed didn't you Jango Fat? If it was you there, it would be hilarious how quickly you are manipulated:
Palps: Jango fat, you must side with me and destroy the republic and kill billions of people around the galaxy.
Jango fat: But wouldn't that be wrong?
Palps: No, of course not, it's the right thing to do, from a certain perspective.
Jango fat: Ok then, since you say it so convincingly, fuk it, lets kill em all, i'm with ya...