From the article:
It is illegal to force anyone to take off their shoes, but passengers who don't comply may be sent to a secondary security checkpoint.
This can't be right (too good to be true). Is is also illegal for a TSA agent to force someone to take their shoes off during secondary? If not, isn't this meaningless?
Edit: Oh, I get it. You're not forced to take off your shoes. You have the option of not flying.