It should be no surprise this kind of bullying took place from wizards. Rowling often tells of the wizarding community’s prejudice against creatures. In addition to the discrimination Goblins often face, wizards have also shunned house-elves, who are enslaved from birth and werewolves, who Dolores Umbridge disparagingly calls “half-breeds.”
Remus Lupin is the most notable werewolf in the series and is used as an example of how cruel wizards can treat those they don’t understand. In Short Stories from Hogwarts of Heroism, Hardship and Dangerous Hobbies, Rowling writes: “The wizarding community is as prone to hysteria and prejudice as the Muggle one, and the character of Lupin gave me a chance to examine those attitudes.”
These creatures, despite the prejudices against them, often work with Wizards. Goblins own the sole bank in the wizarding world, Gringotts. Lupin taught a year at Hogwarts, suppressing his lycanthropy with help from Snape, and house-elves like Dobby do their master’s biddings until they are eventually (hopefully) freed one day.
But Urg the Unclean, and his activism, is a perfect example as to why wizards can only discriminate for so long. Rebellions will eventually rise in an attempt to change how different communities treat one another. It’s no wonder Urg became one of the world’s most notable goblins and earned himself his own card.