It's not eating that's illegal.
It's where he was eating.
And even then, if he had chosen to listen to the cop (as do most transgressors in a similar situation), we wouldn't be having this conversation. But no, he chose to argue with, and then assault, the cop. For which he was immediately arrested. Handcuffed. Which was undoubtedly a possibility that he hadn't counted upon.
(WAT AG)