Agile and DevOps are indeed different things...
Love the article. Agile and DevOps are indeed different things. Of course one cannot blame the public or novices for confusing the two given that there is no formal definition of DevOps. Unlike the Agile Manifesto, DevOps has no such definition, a set of practices, or agreed upon guiding principles. Ask ten people what DevOps is and you will get ten different responses. DevOps is a coined phrase that we are all left to infer meaning.
Agile practices, like Continuous Delivery practices, can be part of a DevOps initiative, but like you said the terms are not synonymous. Among the many excellent points, you made, I agree that automation is critical for DevOps. So many DevOps pundits state that DevOps is a cultural thing, a belief which I do not disagree. However, culture without a repeatable process or system to sustain it is doomed to failure.
Automation is to DevOps as a playbook is to every NFL team. A playbook supports a winning culture, it does not create it nor is it a substitute for it.