The sacrifice of men or animals on whom the burden of sin of the whole community is loaded is something quite different. We know of such acts from primitive cultures too.[...]They also have nothing to do with the materialistic and mechanistic thinking which seems so natural to us. That which distinguishes them from cult practices per se is an idea which must seem just as absurd to the scholarly mind of our day as all cultic matters do. This is the stupendous idea of redemption through a life which has taken upon itself the guilt of all.
This is a passage from Walter F. Otto's Dionysus: Myth and Cult. Otto was a German writer, and I'm reading him in translation, of course.
The book is primarily about the Greek god of harvest, winemaking, fruit, fertility, ritual madness...It's a long and entertaining list. Greek, but very likely adopted from peoples elsewhere in Eastern Europe or Asia Minor.
Otto does not shy away from the fact that the Greeks, like most people of their era, did not just worship their gods in the temple but made sacrifices to them, including human sacrifice. From our present perspective the practice looks barbaric. And I certainly wouldn't advocate bringing it back. But they had an understanding of what they were doing and why they were doing it.