Blame the french for that.
I use KN in my day to day work. And kilopond is not unheard of in common parlance (I don't think it's SI standard, though). I would not expect many people to even care about the subtlety, though. It's not like the units are fully coherent (Kg being a basic unit instead of the gram, and we use calories instead of Joules), but the system is.
Mass is a largely useless measure anyway, but I'll grant you it makes for some pedantic conversations .