We're both right. Yes, the FDA "requires" the manufacturer to provide data to support their experation date, but those chosen dates are up to over 20 years too early, likely to boost profits by encouraging repurchasing over reusing.
"The best evidence of acceptable potency of the medications beyond their expiration date is provided by the Shelf Life Extension Program (SLEP) undertaken by the FDA for the Department of Defense. The aim of the SLEP program was to reduce medication costs for the military. SLEP has found that 88% of 122 different drugs stored under ideal conditions should have their expiration dates extended more than 1 year, with an average extension of 66 months, and a maximum extension of 278 months.3"