In previous times you really had to make an effort to insult someone - engraving this probably took some time.
probably Secundinus had insulted him by shouting at him, making a hand gesture or spilling his beer. But whilst such low effort insults can drive people crazy, they're unlikely to achieve results quite as impressive as worldwide media coverage in future millennia, or historians musing on why Secundinus was considered to be a shitter as they figure out a caption for the centrepiece for a new museum.
That result might impress you, but I think everyone involved would have considered the insult a bigger success if, say, Secundinus' engagement fell through and no one in the future ever heard about the dispute.
Perhaps this would be a nice starting point for a new version of Twitter or any forum.