It's wired as DTE, but with a female connector. *That's* what makes it backwards, not merely the female connector by itself.
If it were a female connector, and wired as DCE, that would be unusual for a computer, but it would still be conforming to the same conventions as everything else. When you buy a random serial cable with male pins in a 25 pin connector, if you know nothing about the insides of the cable or where it came from or what the original packaging said etc, 99 44/100ths of the time that combination expects to be plugged into a modem, or other DCE device. The M100 isn't a modem, but if it's connector were wired DCE, that "modem" cable would still work. *today* such a plug would have an extra dimension of wrongness because it would be ambiguous with a printer port, but at that time, D25F might not yet have become a standard for parallel printer ports. It doesn't matter that the printer port on the M100 itself isn't confusable with it's own serial port, it's still a factor as long as a significant number of printers and their cables out there can physically plug in to the wrong port. At the time, that might not have been true like it absolutely is today.
