Goblins in the Wizarding World have a very justifiable reason to want to wipe out wizards. Humans would see what they are doing as wrong, but humans arent the moral arbitrators of the universe. One species, particularly a wronged and abused species, doesn't have to and shouldn't be expected to treat their oppressors with any kind of sanctity. You think these goblins are being portrayed as evil villains. To me they look like an oppressed and fed up people trying to right a wrong and get justice. And they're trying to do it by using humans to kill other humans. It sucks for the wizards but they have brought it on themselves.
Goblins in the Wizarding World need this kind of development and they need to have complex emotions and motivations. They need to have good and bad members of their species. They can't all be bankers and only ever think of money. That's how good world building works. That's what separates quality fantasy goblins from the caricatures that ignorant racists appropriated to belittle jews.
We'll have to wait and see how it ultimately turns out, but it's my hope that they've done a good job with the goblin characters and developed them individually and as a people.
