Why do the best pan-and French-frying potatoes differ?
Well, from those lists anyway, I think you've overlooked shape and size.

The "pan-frying" potato list is largely of varieties of round potatoes and/or rather small potatoes.  They won't produce very satisfactory french fries because of the simple fact that they aren't very big.  Or, if they are big and round, you're still bound to get a lot of very short fries when slicing near the edges.

For "french fries" you want a potato that's somewhat large and long.  Or at least oblong-shaped, so you don't end up with lots of clumpy short fries.  I'm assuming that for "pan-fried" potatoes, the site your list is from considers that you might dice them or make them into shapes other than long, thin strands.