I have no problem reading constructive criticism of systemd. It has its problems. However, sometimes those critics try to claim that init run levels, or rc scripts, with their arbitrary meaning and the Bourne shell's ad hoc syntax, are a perfectly acceptable solution to the problem that don't need replacing.

I've never seen an OS startup mechanism that tells me, while the system is up, "the change you just made will make it impossible to bring the OS up if you restart it". And that's a real problem.