Screw You, Credit Card!

As I was going through the mail yesterday, I opened up a letter from my credit card saying that it was raising my interest rate from less than 10% to 29.99% Are you kidding me? I haven't had this bad of an interest rate since I was 18! The reason for this was because of all the other crappy credit card holders. It said we could opt out of the new interest rate and they would close our account. Nice! The other option was to accept the new interest rate and "earn" a lower rate back each month by making payments on time. This doesn't make sense if you're already making payments on time. Why should I have to earn back my interest rate if I didn't do anything wrong? Stupid! We don't use credit cards very often, and when we do we pay off the balance every month. Am I overreacting by being so irritated by this?