At that point, Palpatine had not opportunity to refuse to give up the emergency power. He would hold those powers at least as long as Grievous was alive and the jedi attacked him just after Grievuos's dead. Thia is a religious reason. To Mace Windu's best knowledge Palpatine hasn't done anything evil till then.

Once again, Mace Window didnt know that Palpatin controlled the sparatists. That ist exactly what seemed to happen when dooku kidnaps Palpatin.

Ist ein Sith jemand, der die Sith-Philosophie verfolgt? Nein! Ein Sith ist jemand, der innerhalb des Sith-Imperiums die Position des Siths innehat. Genauso wie ein Priester nicht zwingend an Gott glauben muss, sondern nur eine bestimmte Stellung innerhalb der Kirche bekleiden muss. Er kann heimlich ein Atheist sein, das ändert aber nichts daran, dass er ein Priester ist (zumindest solange er das nicht öffentlich preisgibt). Das gleiche gilt auch für Sith. Und zumindest beim Sith Inquisitor ist es durch Gesprächsoptionen möglich, einen Sith zu spielen, der sich nicht um den Sith-Kodex schert. Allein schon deswegen spricht nichts gegen gute Sith.

So he was a enemy of republic not because of something he has done but because his religion is evil (or at least the leader of an other religion said so). That's the very definition of religious persecution.

He wouldn't be a sith by the definition of the two. But he could perfectly be a sith by his own definition and therefor call himself sith. And who told Anikan that Palpatin was a sith? Palpatin himself. So nothing wrong here.

Yes. And Count Dooku tried to murder Palpatin (at least the jedi thought so). So, why would they remove him from his office? Because he has the wrong religion?

That works only if every sith follows this philosophy. If a jedi finds a old sith holocron, he can became a sith, completly independent of the the two sith who exists due to the rule of two.

How could they know it? Beeing a sith is nothing more than just beeing a fore user and beliving in the sith philosophie. So, any jedi could turn any time to a sith if he wants.

Yeah, but Mace Windu didn't know it.

Seriously, at that point, they didn't know he was the mastermind behind the separatist movement. His only "crime" was beeing a sith, or, in other words, having a different religion than jedi. So, this assault on Palpatin was nothing else than religious presecution. Sure, Jedi and Sith had their differences in the past, but is this a reason to kill or arrest this particular sith? To their knowledge, Palpatin had done nothing wrong. Therefor, Jedi are just religious fundamentalist and order 66 was maybe harsh, but perfectly reasonable to save the republic from this extremists.