I make a fudge with condensed milk and chocolate chips that takes about 5 minutes to make. It definitely does not have the consistency of flourless chocolate cake. I melt the chips, condensed milk, a tiny bit of vanillla and a pinch of salt together until the chips are fully melted. It's great fudge.
Also, that recipe is from Sherry Yard, a James Beard-award winning pastry chef. After looking over
her bio, I'll give her the benefit of the doubt and say that she probably knows the difference between fudge and flourless chocolate cake.