I can see your point. I'm not actually trying to justify the obvious corruption in the Republic.
I've just seen the argument that "the Republic is just as bad as the Empire, they just hide it better," and it comes across as silly to me.
If I were living in the Old Republic universe, the Sith Empire would be a frightening place to be, dominated by fear and distrust. You could be murdered by a Sith Lord on the steps of the Dromund Kaas plaza just because you looked sideways at him as he walked by, and everyone else would just look down and pretend it didn't happen.
If you were on Coruscant, at the steps of the Senate Tower, would you expect any Jedi Master to ever behave that way?
I agree and I think this is the root of the argument. I hate to use another Nazi reference but I think it fits well here. The USA has done a number of unquestionably morally dubious things over the course of the 20th century. For instance, interning Japanese Americans during the Second World War. But that doesn't mean that during World War 2, the Allies were exactly the same as the Axis powers.