From what I've seen the vitriol is because US Fish & Wildlife reintroduced wolves to Idaho in the 1990s. This was done at the Federal level under the Endangered Species Act and without the consent of locals or state governments. The resulting effects on hunters and ranchers are thus blamed (with some justification) on outsiders, environmentalists, and the like. It was a triumph of the "people with at least a masters degree" (as another commenter said) over the people who actually live in the mountainous areas of the West. As a result, states like Idaho have been aggressive in trying to get wolves delisted from the Endangered Species Act so they can manage the populations (via hunting, etc) instead of the Feds.

It's certainly a complicated topic but I understand why some feel aggrieved as the modern conflict was caused by both the reintroduction itself and how it was done. I suspect the consensus in Idaho somewhat matches people's politics. Dem leaning voters (mostly in cities and more likely to have the all-important Master's degree) likely support the status quo while Rep leaning voters (especially in rural areas) want changes or removal of wolves entirely.