Their food source was in steep decline due to worldwide commercial whale hunting; extinction is not surprising
In this case, the poster is asking about the claim that the orcas were hunted to be consumed by humans. You didn't provide any evidence that this is the case---and in fact suggested a reasonable alternative---so I suspect you also either question or deny that claim as well.
I think you've fallen into a trap. You've allowed the very people you are trying to rail against here to convince you that anyone asking questions is an enemy of yours and worthy of your derision.
However, if there is documented proof it would make interesting reading, so...