The implication of your comment you're arguing that allowing a species to risk extinction is somehow equivalent to breeding animals for slaughter as a food source. That a person cannot both be at ease with such farming of animals an at the same time, without contradiction, see value in preserving some other species from risk of extinction.

This is a rather obtuse outlook on your part. It should not be difficult to see that these positions on killing animals are not logically equivalent, or logically exclusive of each other.

Even forgetting about any concept of morality or ethics for a moment, from a purely utilitarian viewpoint raising animals for food isn't mutually exclusive with wanting to preserve the balance in an ecosystem in which whales play a part, and whose disruption could have far-reaching implications.

All other things being equal, killing an animal that is in danger of extinction is worse than killing one which is plentiful.

How many cows, chickens etc do you think would survive if humans all of a sudden decided to stop breeding and exploiting them? It's not like those animals can survive in the wild (unless, of course, humans continue protecting them and killing their predators).

Extinction is a problem. Culling isn’t.