Just to get this out there - I have no affiliation with Purism.
But when you buy Purism hardware, you are buying the option of hardware killswitches, and as-free-as-possible modern hardware. If you want to go fully blobless, you can buy a Libreboot Thinkpad with pre-2008 hardware. Buying Purism supports a company that is trying (and I believe making progress) to deblob modern hardware.
You also get a much more aesthetically pleasing machine, at least in my opinion, though that’s a minor point.
And because you control your laptop when you buy from Purism, you can install whatever (Linux) OS you want. There is nothing particularly special about PureOS - it’s a Linux distro like any other. It chooses to have a few things by default, while other distros choose other things by default.
If you don’t like systemd, then install whatever distro you please that doesn’t use it. From what I can tell, PureOS is meant to make Linux accessible to the general public, most of whom have no clue about using Linux at all, and so certainly won’t be concerned about systemd as long as it “just works,” and given Debian, Ubuntu, Fedora, and many of the most popular distros use systemd, I don’t think anyone can really argue that it doesn’t work.
Yes, it’s not really the UNIX way from what I can tell, and it does have its problems, but it gets the job done, and that’s what most people care about. They don’t want to fiddle with settings and config files. They just want to turn on their computer and have it work.