This behavior is different from every other "affects enemy movement" card, such as Reactive Trip or Maze of the Mind. They should all interact with the exact same set of cards, so that we're not left guessing.
There's no guessing. Check the phrasing. Maze of the Mind and Reactive Trip react to 'Move CARDS'. Which, apparently, step attacks count as move cards only when it's beneficial. (No complaints here.) Hypnotic beacon says 'whenever an enemy moves'. It never refers to the basis of that movement. Besides, I like it how it is, regardless of phrasing elements :X
