The difference that makes such an argument unlikely is that with a cblast35 mirror, the comments are only retained for a short period of time, whereas using them in a fortune-like program is to retain them permanently. There is an inherent understanding in posting in the ChatterBox that as a chat, comments there are fluid, and not retained for posterity. In recording them for such a program, however, they become "etched in stone," as it were. (And while there are likely private logs maintained here and there by some, they are not public-access.)
I agree that there is a treasury of comments and quips there that are highly entertaining. I also agree that it is reasonable, if assembling such a compilation, that one ask permission of the speaker to quote them with acknowledgement, or if the speaker would be uncomfortable with such, if they may use the quote and acknowledge it to a monk who wished to remain unnamed (or something along those lines).