I think there was something like that in "fortune" cookies on linux as well, circa 98. It poked fun at OS/2, as you said, and at the PS/2, for being half a computer, perfect for running OS/2.
IBM had a weird obsession with the /2, apparently.
IBM had a weird obsession with slashes in general. If you think OS/2 is small, think about how small OS/400 must be ;)