In certain cases I don't disagree, but systemd does not implement this feature correctly, so using functionality that's easily reviewable from decades past makes sense. If systemd could properly implement the feature, there would be no need for the scripting.

>It has never been safe to kill random processes using a bash script running in the background, on most Unixes (and Linux) it is 100% impossible to do that without race conditions due to the limitations of procfs.

This is hilariously wrong. Lots of UNIX OSes don't even implement the ps suite of tools by using procfs.

Even then, there were no race conditions in this use case anyway.

>You would need to implement this in C for it to have a chance of being safe at all, and even then, you would need to rely on system-specific functionality because there is no portable way in POSIX to actually do this.

It's already implemented this way on plenty of UNIXen. ps and kill is the POSIX portable way to approach this, so you're wrong about that as well.

Almost everything you said above is incorrect, or misunderstanding basic UNIX.