Wu Wei
ursus senum severiorum and ex-Bisy Backson
We've got barely 5000 years of recorded History to work with, but it appears that vengeful gods are politically useful. I have thought of a couple of exceptions to your OP. First I think your size of 1 million is too large, and secondly I don't think that human sacrifice requires belief in vengeful gods.
I don't think you need a million people for that to be true. I think you only need enough for there to be political advantages. Bora Bora had 10,000 people, but it had human sacrifices and religious wars. Likely it was settled about 3,000 years ago by people from Taiwan. Taiwan may have had a larger population, so I can't say for sure that Bora Bora didn't get its religions from there. Its neighbor, Raiatea, was reputed to sacrifice a lot more people. I chalk all of this up to politics, but the religion is part of the sacrificing. This is a classic example of justifying the blood-thirst of a god.
Japan didn't have vengeful gods demanding sacrifice although it had the same religious problems as places that did. For millennia Japan was a place with a History of warfare with many fractious territories. They had executions which were many, but while these were religious in nature they were not called sacrifice. They were related to honor, and honor related to their beliefs about death. The closest thing to vengeful gods would have been demons, but their demons were blamed for evils not worshiped. Even so people were executed for religious reasons. The population was in excess of 1 million, yet there were no vengeful gods -- and yet religious executions appeared anyway.
Same can be said for Taoism and Buddhism in China. Or Buddhism in India. Had more that enough people, based on the article, to come up with vengeful Gods....but they didn't