Not once did they raise a moral objection or question that one of their own would have order such abominations. The Senate and the Republic were left but no choice but to use the army the Jedi offered them. All those planets including Mandalore and there were no mercenary armies to be had?

But given the choice of allowing a the Trade Federation to take a few planets until a real army could be built or accepting genetically modified slaves clones that lack the will to resist and would serve no purpose once the war was ended and who would not be fit for society yes they should have taken the hard road. They were not aware that the Chancellor could order the clones to kill them even though that had every reason to suspect this army of horrors that just happen to conveniently be ready when they needed them. So the not only slave masters but fools.

You can argue that the lack of free will disqualifies them as slaves but only because they are something much worse. Sentient emotionless killing machines that following any order without question? That is worse than Janissaries. The Janissaries were highly affective but they were formed but stealing and abusing children. You could use the to attack and slaughter their own people. Clones are worse.