Propagating the niceness of a process by default is perfectly normal and most OSes do it by default. E.g. Windows propagates IDLE_PRIORITY_CLASS or BELOW_NORMAL

Propagating the niceness of a process by default is perfectly normal and most OSes do it by default. E.g. Windows propagates IDLE_PRIORITY_CLASS or BELOW_NORMAL_PRIORITY by default. So much of the "Unix processes" theory. Given systemd did not stop to use "Unix processes", that should also have been a clue. The issue was about the postinst script which either missed that it should have done something differently, or is maybe just not designed to be run nicely so the users broke an (implied) contract by calling it that way.