You're trying to use logic and reason as they apply to the government. The dirty secret is: they don't. Ever.
They were banned because if a child swallows two of them, then they'll pull toward each other, possibly ripping a hole in the intestine.
That said, you can get spherical rare-earth magnets here:
https://www.kjmagnetics.com/products.asp?cat=12
...though a set of such won't be cheap, depending on the size of the magnets wanted.
Only problem -- if a little kid or animal swallows at least 2 of them, then they can pinch some intestines together inside you and be stuck there and kill you.