Sure, but there are far more diplomatic ways to do it, too, and given the status and gravitas that Carlsen has as a name and a voice in the chess community, to just go "take ball go home" and then resign by switching the webcam off and tantruming out of the room, rather than actually say anything about what he wasn't happy with (leaving us with that Mourinho interview post) while speculation ran wild?
Even if he may have been right about Hans, and certainly there had been plenty questioning him before all this kicked off anyway given his history and rapid development, if you didn't know who either of them were and were just given their ages, you'd have been forgiven for thinking Magnus was the teenager and Niemann the 30-something from their behaviour after the game that sparked it.