The difference is most animals don't have an outside perception of nature, or when hunting. We do. We KNOW that Whales are intelligent. We KNOW they are endangered. Why should we have the right to wipe out a species just because we can?
It's FAR worse than killing livestock. Livestock are (for the most part) killed humanely and killing them does not effect their species number as they are bred to be killed. And a pigs intelligence compared to a Whales is absolutely laughable.
Whales can problem solve, have been proven to be able to show emotion like love, grief and joy. They live in complex social groups and have advanced acoustic processing, communication and social intelligence. They are also one of a few species that are self-aware.
Pigs role in their own filth.
The way the Whales are killed, is inhumane, brutal, and beyond painful for them. A few whalers even use grenade tipped spears that detonate after they have penetrated the Whales flesh. It takes minutes for them to die, after being hauled out of the water.