Or they would have taken the only leash off the Jem'Hadar, loosing a vast horde of now-uncontrolled drug-addled rage monsters on the galaxy, killing vastly more people.
Look up the term "blowback."
An army of crazed killing machines bent of revenge is far LESS dangerous - both tactically and strategically - than an army of disciplined killing machines, obeying a long-term strategic vision which includes numerous genocides/conquest/genetic slavery/etc, etc.
The former is a pack of locusts - destructive, but transitory.
The latter is a meat grinding machine which will cause death and suffering for millenia - with impunity.
No, not "unaccountability." Unaccountability, full stop, no quotation marks. Defiance of the law. Criminality.
The law is not always equal to morality; or the actions that save the most lives/freedoms.