No, sorry. I know Wikipedia isn't the bible but they had a bunch of different reasons for the term cracker.
The one that I had heard most is the one they describe as apocryphal, that is that the term cracker came from slave masters cracking the whip.
I always thought this was a reasonable definition of the term and thought WTF, call me a cracker, big deal?
I don't mean I wanted to be a slave master but that calling me the name of someone in the position of power isn't the worst thing you can do