The Capacity for Loathing?

[Beleglas]

Orcs we can assume are the twisted form of both Men and Elves from the information we glean from 'The Silmarillion'. However, what I wonder is which of the races held the greatest capacity to hate the other?

If I remember correctly (and I believe I do this time), the first Orcs were only Elves who were captured Morgoth and tortured to the beings they are now. He made trolls for the same sake by torturing ents.
Don't forget that elves must have been changed for they would never be minions of Morgoth in their own will and men are easily enough corrupted into the service of evil.