Korman was dismissive of the change during Tuesday's hearing, saying the FDA still hasn't presented a scientific justification for any age limits.
"I'm convinced the only reason you decided it when it was decided was to sugarcoat this appeal," he told the FDA's lawyer, according to Reuters.
He said the complicated logistics of enforcing the 15-and-older age limit are "what happens when you let politicians instead of scientists make these decisions."
The age restrictions are especially onerous for younger and poorer patients, as well as minorities, who are less likely to have government-issued identification.
According to the Wall Street Journal, Korman said it's "intellectually dishonest" for the government to argue that such limitations don't matter in the case of Plan B, when it aggressively makes the opposite argument about voting rights.
Korman is expected to decide by Friday whether to grant a stay.