I think there's a point to the blog article itself, but i think you miss a vital point in the conclusion. The way a DevOps position that is described in the blog post is a valid position that could have DevOps in the title. But that's not usually how the DevOps role is used. This can be easily seen in many listings of the job title.

The analogy with agile is pretty good here. Sure you could have an Agile Engineer, that works primarily with making sure the agile process is actually used and help facilitating that. Normally that would not be a position itself though, especially not an engineering one.