The creation of the clone army was orchestrated by the Sith, but the Jedi seemed to show no qualms about using this army of clones genetically modified for obedience and bred for the sole purpose of fighting and dying for the Republic (and, by extension, the Jedi). The Jedi are generally considered to be the "good guys" of the Star Wars universe, but this use of the clones is arguably a major moral flaw on the part of the Jedi.
I know of one case in which the Jedi were accused, in-universe, of exploiting the clones: a clone sergeant nicknamed Slick betrayed the Republic by working for the Separatists, and at one point berated Anakin Skywalker and Obi-Wan Kenobi of using the clones as slave labor:
Slick: It's the Jedi who keep my brothers enslaved. We do your bidding. We serve at your whim. I just wanted something more.
Rex: "And all you had to do to get it was put the rest of us all at risk."
Slick: "I...I love my brothers! You're too blind to see it. But I was striking a blow for all clones!"
Cody: "If you loved your brothers, you wouldn't have put them at risk."
However, Slick's accusation was not made in a situation in which the general public would hear the charge (e.g. in the Senate or to the media), so in that case the Jedi did not need to justify their use of the clones to the general public. Even though Anakin and Obi-Wan were present when Slick accused the Jedi of enslaving the clones, neither Jedi bothered to defend the Order -- they left clones Rex and Cody to respond to Slick.
Owing to the obedient nature of the clones, there aren't a lot of cases where a clone expressed a desire to leave the service of the Republic. Aside from Slick, I only know of the deserter Cut Lawquane. But surely the Republic and the Jedi knew there was a possibility that a clone would not want to serve, in which case they would need a policy on handling such situations. Moreover, the validity of any clone's consent to serve is questionable given that clones are genetically modified for obedience and raised from birth for the sole purpose of serving in the Grand Army.
Were the Jedi ever publicly accused of exploiting the clones? If so, how did the Jedi attempt to justify their use of the clones? Did the Jedi have a policy that clones who wished to stop serving in the Grand Army would be permitted to do so? Note: Answers from Legends are acceptable, though I prefer canon answers.
[Further background reading]: Out of universe, the Jedi have been accused of exploiting the clones at least twice. The Clone Wars director Dave Filoni questioned the Jedi use of the clones as part of a discussion on Slick's character:
It is one of the things I think is an issue in the Clone Wars, is how can the Jedi Knights use these people as a military, knowing they're basically bred for combat? And this doesn't sit well with Slick; he doesn't see it evidently as being an honorable soldier, like Rex does. I mean, Rex is the good soldier; Rex and Cody, they're very loyal, very honorable. They have all the qualities that I think a hero has, and yet Slick sees them more as, you know, cannon fodder.
The Jedi were criticized more harshly by Star Wars author Karen Traviss, responding to the question "Is it true you hate Jedi?" on her blog:
But once you're past the age of puberty and you start arguing passionately with me that the Jedi were right to accept a slave army of cloned human beings and use them in war, and cloned humans aren't proper humans like us, and it was too bad the clones died, and the Jedi had no choice - well, sweetheart, I want to run a mile from you. Not the Jedi, who - just to remind you - are a figment of various writers' imaginations, just like the clones. You. If I see that you really mean it, and you're making excuses in your own mind for the Jedi just following orders on that delicate point, then you scare the living crap out of me. For real.
Traviss goes on to say that if you support the Jedi use of the clones in this way, then you are thinking like a slave-owner and/or Nazi for considering the clones less than human.