I have no clue what you're supposed to say, but the closest thing I'd have to a 5-year goal is "increase my net worth by at least 20% per year". Which has almost nothing to do with my job except staying employed.

So you have zero goals in life? You expect to die as you are now, but older?

"Be managing a full project on my own", "Manage group of people", "Become an expert in X technology", "Build 2 products into production", "Get to 100,000 users" etc etc etc.

How do you want to grow? Do you want to stay in the same spot? Maybe for now, but do you want to be doing this exact same thing for the next 5 years? Not even minor improvements? Getting faster/better/stronger?

OK, but that doesn't change the point of their post. It can easily be rephrased as something like...

"Would an employee feel honest telling their boss their 5-year goals? What if it isn't "leading a larger team at this company" or "designing and developing more and/or more-important portions of the company's projects"?