i don't think it's so much that they're actually the baddies as it is that they became too dogmatic and process-oriented to be able to do the good that they were trying to do. on the micro scale they were too inflexible with their rules to always do the right thing, and on the macro scale they could bend the rules however they wanted in the name of The Greater Good. protecting the Jedi order so that they could hypothetically do good later was more important than admitting to mistakes and exposing themselves to criticism to do tangible good in the moment. in less words, they meant well and had their heads pretty far up their asses. the Dooku episodes of Tales of the Jedi demonstrate this very well

whether or not this is just the Jedi Order or the larger light-side-user community is up for debate. a lot of people point to the prophecy of balance being brought to the force and say that that required an equal number of Jedi and Sith, and that idea seems to have seeped into Disney canon, but at least originally Lucas seemed to intend for the light side to represent balance and for the dark side to be a corruption of that, in which case the Jedi Order being assholes meant they also weren't really Jedi to begin with

another commente argues that of course they're assholes because they're a religion, but i'd argue that they're assholes because they're an organized religion. if being a Jedi is about harmony with all life and the force, as opposed to using it and abusing it, you can't create Jedi by using and abusing life forms the way a beaurocratic institution invariably does. it's not a coincidence that all of the great Jedi heroes throughout SW are either deviants within or otherwise estranged from the order. standing up for people and doing the right thing almost always involves sticking it to The Man, and the Jedi Order were The Man