Blanchables

To get the first iron ores, you need bear-mining set and bronze pickaxe to mine it. You get enough to make a hammer, pickaxe and saw. You try to make Sturdy Tool Rods, realize bronze saw can't make those unless you have bear-carpenter set. Kills another 50 bears. BAM, now you need 150 bears instead of 50 to progress, economy. 😉

when societal progression requires the wholesale slaughter of hundreds upon hundreds of bears

Aren't we around a thousend as multiple communities all tries to reach the same progress?