rather than requiring you to write a long response, i think it just means that they want you to write no more than one page ...
in other words, i am reading the instructions as "it's really up to you, whether or not you want to write just a small paragraph or to fill up the whole page. just don't go over a page... or else!! 😡😡😡"
j/k... In my opinion, as long as we get our point across we'll be just fine.
The answer to the question "Why Georgetown?" is very important to them. At the interview, they stressed that, "If you don't know why you want to come to Georgetown, we don't want you here."
Thus, give their secondary some thought.