It took one episode of tales of the Jedi to really show how the Jedi had become a tool of evil, whatever their own intentions. They built a system of rigid rules and absolute loyalty to a group that weren’t beholden to their rules or morals. So when that group started getting corrupted, the Jedi helped enforce that corruption.

If Palpatine was doing everything he was but just wasn’t Sith, I doubt the Jedi would have even tried to do anything about him. Political power, just like the force, can be abused. Good people don’t abstain from power and obey it unquestionably. They question it and its motives constantly and fight it when it conflicts with what they believe in good faith. And occasionally break it when it becomes irredeemable.

Which is something I don’t like about the new Star Wars: it’s pretty hierarchical and I can think of several times where orders conflict with morals and each case seems to have the “lesson” that authority is the one in the right, or at least never challenges authority being upset about being disobeyed.