systemd is 100% free software, unlink Windows. systemd has a command line interface unlike most Windows tools. And I don't know what is the Windows init system but I doubt it is similar to systemd. It's probably much closer to the Mac OS X init than Windows'.
Seriously, it does not make any sense to say that systemd is a "Windows" approach.
Not only is it Free Software, but LP was nice enough to make the entire thing accessible over RPC, so that non-free software could easily integrate with the OS at the lowest levels (PID1!), bypassing GPL/LGPL restrictions, and removing much of the reason to write Free Software on Linux at all.
How this isn't worse than Tivo-ization (the reason the GPLv3 was written!), now how RMS/Moglen aren't screaming about this, I'll never know.
Seriously, it does not make any sense to say that systemd is a "Windows" approach.