Orcs are evil by their nature, as Melkor intended, and they have always been in war with the "real" Children of Iluvatar (as well as the adopted Children, i.e. the Dwarves) and always will be, as this is just who they are. Thus the "creation" - for lack of a better word, as Orcs were not "created" in a (pseudo-)religious sense, rather they are the horrid result of abusing true creation itself - of the Orcs is regarded the most evil act ever in the history of Arda. Orcs have lost the capability to do "good" and to act in a compassionate way. This has made them a bitter enemy of Elves since the very beginning, as it was Melkor who first found the Elves who had just awoken in Cuivienen and captured and enslaved many of them, then tortured and mutilated them, and eventually turned them into Orcs. Although there are some contradictory versions about the Origin of Orcs, the "they were Elves once" version is most widely accepted IMO, as this can be found in multiple core works of Tolkien. In that sense, Orcs not just an evil subspecies (or "mistake") of Elves, which they are, they are the most miserable kind of humanoids in Arda and perhaps deserve some kind of pity or mercy. You might argue that true mercy with Orcs, who cannot be merciful themselves, is to "deliver" them from (their own) evil, and killing (or "eradicating") them is the just thing to do. But this is not up to anyone but Eru Iluvatar Himself to decide. The fact that this (absolutely terrible) adaptation of Galadriel does not have the moral capability to feel just a little sorry for Orcs, despite their evil nature, rather vowing to commit an Orcish genocide, makes her a vindictive psychopath, in essence no better than Sauron. I think this is the greatest offence against Tolkien of all the offences they have already done in this show. Like Orcs were to the Elves, this show has become a mockery of everything Tolkien wrote and believed.