Are people seriously advocating for systemd to be a babysitter for the root user? I would definitely be more upset if systemd posed restrictions upon what I was allowed to do (as root). But, sure, I understand the problem (which Etcetera seems to be the only one to touch upon) that systemd makes it harder to strengthen the security by generally limiting the possibilities to customize your system.
People who come from a DOS/Windows background also seem to think that "rm -rf /" should be expected to work like "format c:". But the root is not just the (first) harddrive and as a user of Unix (where "everything is a file") I would rather translate it to "delete everything there is to delete, yes really". I wouldn't find it strange if stuff on the network got deleted too, not just regular files but printer queues and whatever. Not to mention all sorts of flash memory of any sort of attached device.
If anyone is to blame here it's the BIOS developer I think. A more robust implementation would have some fallback code in ROM that lets you at least install a new flash image. But while PCs have generally been quite robust (until now), where have been other more easily bricked systems. Sometimes you can remove the flash IC and rewrite it. Sometimes you just have to toss the hardware. It's annoying but it doesn't make me blame the software for not preventing me from doing the mistakes I did (which wasn't simply running "rm -rf /" by the way).