From the pdf you posted
"This notice provides guidance to U.S. and foreign air carriers regarding compliance with the customer service rule that requires carriers to hold a reservation at the quoted fare for 24 hours without payment or allow a reservation to be cancelled within 24 hours without penalty (the “24- hour reservation requirement”)."
Until recently AA were offering the 24 hour hold option and not ability to cancel without penalty within 24 hours. Both methods are in compliance with the regulation.