Just so. But that straight-through / null modem / gender changer mess had serious consequences. Equipped with a gender bender, any slightly intelligent user who didn't know better could figure out all by himself that all he needed to do to get the parallel cable to fit into the serial port correctly was connect the gender changer. Worked first time every time. (Assuming that by "worked" we mean "let the smoke out", of course.)
And then there were those DB-9 monitor connectors (back before 15-pin VGA became universal). They were fine, nothing else would fit in them .... until modern 9-pin serial ports started replacing the old DB-25 style and instead of blowing up $25 serial ports by plugging them into $200 parallel printers, we could blow up $500 monotors by plugging them into serial ports.(Or was it the ports that blew up. Can't remember now.)
Anyway, I used to teach people that the only thing you needed to know about using gender changers is don't.
Which brings me to the ridiculous visual similarity of HDMI ports on laptops and USB ones. Right next to each other too, and every damn thing is (a) out of sight under the stupid curve in the laptop case edge, and (b) black on black. Haven't managed to blow anything up that way yet, but there is always hope.