I can understand why you are upset, but I don't see why it is unfair for Disney to treat the two groups of customers: those who opted out and those who didn't, differently here for two reasons.
First, they are compensating the customers for the inconvenience of having to scramble to change travel plans at the last minute, despite very high call times, and despite the fact that they may already have flown/driven down to Florida or incurred other non-refundable expenses from the last-minute cancellation. We flew Southwest once during a winter storm, had a long exhausting day of delays, rerouting etc (3 hour flight became a 12 hour ordeal with small kids), and received a $100 per person credit from Southwest. Under southwest's policy, we could have cancelled or rebooked up to 10 minutes before the flight and gotten credit for what we paid, but we got additional compensation because we experienced difficulties that people who did cancel or rebook did not.
Second, they are rewarding people who would have sailed with them and lessened the financial blow to them. Like Southwest in my example, if we had cancelled, they would have flown a closer-to-empty plane which is costly for them. Likewise, if Disney had not had to cancel the March cruises, your cruise would have gone without you and the many others who opted to rebook, which would have been costly to Disney because they would have been sailing with fewer paying customers but still have expenses for staff, fuel, food etc. So they are giving them better perks as thanks to those people would have
saved Disney money, whereas people like you who cancelled would have
cost Disney money.
I don't say this to be unsympathetic--I know how sad I will be if I end up not being able to sail on my cruise. But to envy people who are getting compensated for a greater inconvenience than you had, and who are being rewarded for taking on risk that you weren't willing to take and that helped keep
Disney Cruise Line afloat, just doesn't make sense.