The XZ backdoor. That's why.
Only Rube-Goldberg complexity on the scale of systemd made the XZ backdoor possible. Systemd was made by despicable individuals who went on to work for despicable companies (as a big fuck you to open-source lovers) and then later on to work on even more despicable surveillance project (as a big fuck you to humanity).
systemd has its tentacles meddling in every single part of the Linux ecosystem.
But thankfully there's light at the end of the tunnel: thanks to VMs and containers and the need for speed, we've seen many minimal distros (I'm thinking stuff like Talos for Kubernetes) and those of course don't use systemd.
As soon as I get the time to switch away from my current hypervisor (Proxmox, so Debian, so systemd) to an hypervisor not running under Linux, like maybe bhyve on FreeBSD, I'll have all my VMs and containers and hypervisor totally systemd free (my VMs and containers are already systemd free: I did in anticipation of, at long last, giving systemd the middle finger).
But of course none of this matter much because according to HN we're already at a point in time where we can write: "Plz rewrite an init system".
The real question is: why don't people hate a rube-goldberg init system made by someone who went to work for Microsoft, while using crypto made up by his brother (certainly secure we're sure), and who then went on to create a full-on surveillance company working on locking down hardware?
Regain control of PID 1 people.