Oh for fuck's sake. It's a parameter passed to the kernel. Programs shouldn't parse it for precisely the same reason why Firefox doesn't parse sshd's arguments. I.e. because they're passed to sshd, not to Firefox.
It's a ridiculous clunky hack that stinks of large company coding practice: what they actually needed was a way to pass arguments to systemd itself.
The logical way to do that in an OS that has to be portable and flexible is to implement a mechanism for the kernel to pass some of the arguments it receives to init. Because there's no reason to assume that init is going to be systemd, that there's going to be a procfs ready for it so as to be able to read the kernel's parameters, or that the init process can read it for that matter.
The way the systemd development team chose to do that (widely seen in many other projects from the same lineage, like Pulseaudio) was ha look at that we can see the kernel's arguments so how about we use those and what do you mean "this can have unwanted side-effects", it works perfectly fine on my system.
The fact that the developers (again, it's a known pattern) decided to play the PR game and call it "expected behaviour" doesn't make it less of a bug. It's also expected that a division by zero will crash your program. It doesn't mean that blindly accepting any input values is not a bug, nor that the correct way to solve "your program crashes if I pass 0 as the first argument" is "well stop passing 0 as a first argument ya evil bastard."