Why Witches Ride Broomsticks: A Theory

I noticed an interesting detail in this article on How Witches' Brews Helped Bring Modern Drugs to Market. We all know that witches ride broomsticks, right?



Also, witches liked to anoint themselves with psychoactive herbs: "witches applied the salve to their skin—either under the arms or (for the daring) on the genitalia." 
And:

A 1324 inquisitor’s account of a suspected witch, Lady Alice Kyteler, does paint an interesting image of the ointment in action:

In rifleing the closet of the l...