He rants about systemd, then talks about liking CoreOS, which uses systemd for everything. He is contradicting himself, but I'm genuinely not sure of why.
Author is saying that CoreOS is a good solution because you use it with heavily isolated containers. Thus, any use of systemd is unable to screw up hosted applications. For that use case, it makes sense, whereas in more general use, systemd wants to get all up in everything.