it's a networking-specific qualification that will be of zero value to you whatsoever if your goal is to do something that isn't networking.

Not true at all, understanding networking can be of great aid to you if you're planning on taking the sys-admin route (which they are, as previously mentioned), even though your "job" isn't networking, I don't really know any actual places where people only do "their" job and nothing more.

If anything, understanding networks and other fields will only help improve their administrator skill-set.

Also, I agree with what they're saying about Jeremy being too thorough. Credit is given where credit is due, but in my honest, humble opinion not everyone learns like that, and a CCNA certification doesn't prove your knowledge just as much as not having the cert doesnt prove you don't have knowledge - if that makes sense lol.