And the programmer in question has a reputation for blaming other systems when it is their fault.
A lot of programs follow the unix philosophy of "be strict in what you send, and liberal in what you accept". Lennart doesn't do that. He does "be strict in everything you do". Which is why so many of his previous programs have been such a pain - he refused to work around bugs etc in other programs, and just complained and complained until they were fixed.
Unfortunately, in the meantime, things like Pulseaudio didn't work properly :-(
Hence the decision that systemd would assume the things it needed were there, I suppose. And then Lennart made sure that, in linux at least, they were. If other people want to port systemd, they need to make sure the things it needs are there.