What means “system engineer practicing DevOps”?
What the comment means is that DevOps is a way of working, a culture if you will, not a job title. There are plenty of blog posts about it.

While they have a point, one could also argue that Cubism is a way of painting, but "cubist painter" is still perfectly valid.

This is a potentially long and opinionated discussion, which is out of scope of this forum.

The point is, the definition of DevOps is too lacking on specifics about what exactly the person practicing it does and what kind of tools they use to do it to be of any actual use as a job title. Which is why it is often misunderstood and misused. And there is (almost?) always a better title to describe the job.

For example, if your job consists of solely setting up pipelines in Jenkins, then you might get slapped with the title "DevOps Engineer". However:


A job that specialized would be contrary to the idea of DevOps in the first place.
"Jenkins specialist" is a more apt title. Just an example, there are better names for it.


The title is avoided by most companies these days, often replaced by "Automation Engineer". Which, while still vague, it is less so then DevOps Engineer.

Going back to the specifics of the comment, many times the people that installed Jenkins (and the like) in a company were the Systems Engineers. And they probably also explained how it works to other people in the company, maybe even used the term DevOps to explain the philosophy behind it. Which is why the two are often confused. "The guy that takes care of Jenkins? Oh, you mean the DevOps guy? Yeah, DevOps Engineer". No, he's a Systems Engineer practicing DevOps. If nothing else, he should know a lot more than just Jenkins.