The disniction sould be made between people, not lumping people into sterotypes. Anybody who would lable themselves as a hacker has done some cracking in the past so wouldn't they also be a cracker. Otherwise how could they gain those skills and knowlage. If they are not breaking in for personal gain then that is the hackers choice not because he is part of a fundmentaly different group.
By the same token, anyone who would call themselves a cracker would still fit the deffintion of a hacker at least part of time. They would still aid security by defualt. The person would still be "seeking knowlage".
These groups and sterotypes are reversable at almost anygiven point in time. To differentiate between them just doesn't do any good. They are the same thing.
