As much as that wasn't what you wanted to hear, it makes sense. If you just changed the dates on your current reservation, then any money you had already paid toward that reservaton would continue to stay on that reservaton. To only have a deposit applied would require a new reservation and cancelling your old one - which brings the $200 penalty into play. Sorry you didn't have a better outcome to your situation.
That's one reason I book room only reservations. I like the fact that I can cancel up to a week ahead and get my deposit back, and I like the fact that I don't have to pay for the room until I check in. But I have also booked packages a few times when they were a better deal than RO and I did worry up until a couple weeks out that something might happen to cause the trip to be cancelled (I suppose I could have purchased trip insurance, but it covers so many things that wouldn't apply in my case that it just seems like a waste of money for me).