[1] https://www.feynmanlectures.caltech.edu/II_36.html
[2] This intuition debunks many types of incorrect "infinite energy of magnets" ideas that lead to perpetual motion. Although it can't debunk the "perpetual motion solely from an uneven static (electromagnetic or gravitational) field" idea, which is even older.
Spin is a type of intrinsic angular momentum that is not associated with any spatial motion.
The Feynman lecture you linked to is an explanation why currents fail to explain ferromagnetism. You need to read the next chapter, but being a lecture for undergrads, it doesn't go deep into the subject anyway. If you're really interested, any modern book on magnetism would be much helpful.
If you wouldn't mind reviewing https://news.ycombinator.com/newsguidelines.html and taking the intended spirit of the site more to heart, we'd be grateful.