I think it's kinda cool, it's Gibsonesque, and that usage is old enough now it's rolled from awkwardly dated back to cool, especially now that people no longer tend to talk about "cybersex" and many of the other uses of "cyber".

You've got to call it something, and calling it "cyber" differentiates it from all the other kinds of security. I doubt it means much to talk about "security" to the government, that could as much mean a missile system, but I don't know, that's not my area of work.

To us developers who work with computing all day it feels cringe because the cyber part is implied, and "security" is the differentiator., so you can just talk about working in "security" or "infosec".

Is "cyber" a bit of a relic that dates when the government started taking it seriously? Of course, but I don't know if there is a good alternative that doesn't have other connotations. It probably also acts as a bit of a shibboleth in both directions, "cyber" for those in the government sphere, "infosec" in the commercial.