So I've been on USCG OCS interview panels too, and have to disagree with the Commander. I absolutely do NOT expect an interviewee to have a career path planned out, and even if they do, the answer seldom ends well. Here's why.
If you pick something too supportish (like Health Admin), I'm thinking you're not really interested in CG missions or being an active duty officer. Why bother at that point.
If you pick something that isn't even a CG officer career path, clearly you haven't done your homework.
If you pick something too glamorous (like search and rescue helicopter pilot), my next question is always "that's a competitive process, what would you do if not selected for that?". People very, very seldom have a good answer for that when they've already got their heart set on something that may or may not happen, and they won't know if it's gonna happen or not until after they've already become an officer and have a service commitment. You come across as rigid, inflexible and not able to adapt to change, none of which are good things.
The thing to understand about becoming a CG officer is that you do what the Coast Guard needs, which might not always be exactly what you want. The other thing to understand is that while the CG of course needs people in support roles too, we're an operational service at heart. So, my recommended answer to the career path question:
"I'm interested in becoming grounded in Coast Guard operations, perhaps initially assigned afloat or in a Response Department at a Sector. I understand that I'd serve where the Coast Guard needs me, but I'd really like to first experience the full range of Coast Guard missions before making long term career decisions".
Stick to that, it shows that you're interested in CG operations, understand that assignment is about needs of the service (not you) and that you're open minded, adaptable and willing to learn, all key traits of a good CG officer.