People don’t like it because it’s declarative. It felt cool to be able to just put bash files into certain directories to have them executed on startup. That was elegant, in the sense of “everything’s a file”.
systemd is more of an api than a framework, so it’s a different design paradigm.
I hated systemd until I printed out the docs, for some coffee, and sat in a comfy chair to read them front to back. Then I loved it.
Mostly I hated it because I didn’t know how to do things with it.
Also, “journalctl” is kind of an ugly command. But really, who gives a fuck. It’s a well-designed system.
And if a person absolutely must execute their own arbitrary code they can just declare a command to execute their script file as the startup operation on a unit.