Yeah, that is from a Roman punishment called
poena cullei which was used to punish those who'd killed their parent(s) or parent-like guardian. It's a strong design move that suggests certain lore – namely, that the hezrou acted against its creator/commander in some way.
Which ends up being the opposite of how they're depicted in past edition D&D lore – as unusually loyal and steadfast for demons. And it's the opposite of the historical figure – Hezro of Carmelite – who seems to have been one of Gygax's creative inspirations for the hezrou.
Not that it's totally irreconcilable, but there'd need to be some really strong lore-building to support such a divergence.