I don't think "Unix philosophy" means "communicate via streams" in this context. I think it means things like the single responsibility principle. Once we introduce APIs, we can't just chain services together with pipes.
But I agree that this use of "Unix philosophy" is confusing.
I think the original sound-byte I was trying to capture was "do one thing" which in my opinion neither Kubernetes nor Systemd do. To be fair -- neither would Aurae. So I just scrapped the entire comment.
I wasn't trying to nitpick systemd as much as I was trying to draw attention to the fact that it does in fact -- get nit picked -- and often unnecessarily.