> kill [...] shell-typed command spawned directly or indirectly
are you sure? let's assume you typed "service httpd start". it starts the init script which starts the httpd in the background. IMO most in use-cases you don't want to kill everything ever forked from the current shell.
As well as getting how "service" commands operate wrong, you are conflating a "background" process associated with a TTY with a daemon. Some "service" commands work the way that you describe. But that is actually a bug. A properly designed "service" command does not execute as some direct or indirect parent process of the eventual "httpd" process. The "service" command runs in a login session. A daemon has (at least as an intention) no association with a TTY. The daemon process runs in a context that has never been tainted by any of the various things associated with login sessions.
are you sure? let's assume you typed "service httpd start". it starts the init script which starts the httpd in the background. IMO most in use-cases you don't want to kill everything ever forked from the current shell.