I haven't read it, but the description you give of Henches sounds almost like an allegory for how people irl might work for, say, corporations or organizations that inflict measurable harm on society & what the employees' degree of culpability in that harm might be. But based on the rest of the post I suspect that is not where the book is taking things.

(FWIW: I am mildly interested in superhero stories that critique the collateral damage that heroes cause, but it also sounds like this book wouldn't scratch that itch in a satisfying way for me.)