[Son of Númenor]

I did a search on this topic and found this excellent response to the question at hand:

Originally Posted by Sharkû

"They [sc. orcs] would at least 'be' real physical realities in the physical world, however evil they might prove, even 'mocking' the Children of God. They would be Morgoth's greatest Sins, abuses of his highest privilege, and would be creatures begotten of Sin, and naturally bad. (I nearly wrote 'irredeemably bad'; but that would be going too far. Because by accepting or tolerating their making – necessary to their actual existence – even Orcs would become part of the World, which is God's and ultimately good.)" (Letter 153)

"I actually intended it to be consonant with Christian thought and belief, which is asserted somewhere, Book Five, page 190,1 where Frodo asserts that the orcs are not evil in origin." (Letter 269)

What else is there to say?
I believe we have had this discussion at least once before, but for this thread's sake, let me add that while the notion of orcs being corrupted Elves may have been the idea at the time of Tolkien's writing of LotR, later theories should be given more importance here.

What the quotes tell us is that there is of course perfection, but it lies solely with the Creator (and one might say therefore in creation as a whole). Because of the gravity of the origin of orcs, which does not change with a different idea of their beginnings, they are indeed "naturally bad".
Furthermore, it is stated somewhere that orcs in fact loathed their own existance.

(From Inherent Evil)