They use the first element. Like, it's random enough, right? :) (I mean, it still works, but goes badly for lists already sorted in reverse, etc.)

There's no problem with randomness in FP?

You could use a monad/external state for an OS-level RNG, or define a purely functional PRNG

It's usually quicksorting a linked list, where a random pivot, median of three, etc. are terrible for performance.

(Merge sort is of course the natural sort for lists, but qs is like 2 lines of Haskell so it gets demoed for being clever)

Just do the Sedgewick thing and take the median of the first, middle, and last elements.