If death penalty alone is FUNDAMENTALLY bad and is morally just as wrong as murder of innocents...

… why haven't certain legal institutions and places in the world, if they aren't totally barbaric themselves, have abolished them on moral grounds, and if it really is "murder" just like killing innocent people is murder, why hasn't anyone sooner or later been punished for it or stopped in the first place?

Or is it REALLY like that despite what some may say - and if we do hear them say it, can't we just collectively disagree or dismiss it as non-sense? As in, is it REALLY in and of itself just as bad and immoral as when criminals kill innocents?

P.S. Oh yeah, so OK death penalty we see as bad, even if it doesn't touch innocents by mistake. But stuff like imprisonment and also say bad conditions in prison - can we at least REGULATE it all? But jailing someone alone or rather jails and prisons aren't bad even with mistakes, no matter what crime was committed, but death penalty is? What if death penalty was only administered in extreme cases and with like perfect proof? And with regards to stuff like brining grief and pain to even criminal's relatives, well... Even without it people do it, and its understandable at times, but then again, what is a more humane alternative? And most relatives feel sad and grief even for their criminal siblings at times for a variety of reasons, but then, if they get killed in self defence?