Nah, this totally makes sense. Revivify costs 300 gp, which is about 5 months of work for a skilled hireling (or 4 years for an unskilled one). Laws are only for the poor.
If you convert to the relative value of labor instead of the real life value of diamonds, it’s probably something like $40k to $60k to revivify someone. Seems like enough cash on hand to somehow get away with murder.
Are you are suggesting Blades in the Dark is some kind of derivative of D&D? If so, that is a very hot take. And even if you like 5e, imo, Pathfinder 2e is right there doing the same thing but better.