PEDs aren't just for body builder physiques. They are also used for recovery from injuries.
If Peyton were truly outraged by the report, he would have sued for defamation as would all the other NFL athletes, but he didn't because he knew better. He would have opened himself up to the discovery phase and ruined his legacy.
Peyton is dirty. He was desperate to return to his former form and used performance enhancing drugs to achieve it. He isn't the first guy to do it and he won't be the last.