That statement its true but I also feel that its an oversimplification. If we understand fun as playful pleasure I believe that it fells short. There are many kind of games. Games that make you think, others that make you feel "fear" or tension, games that give you adrenaline rushes, games that make you laugh, and even games that become a "work" ( profesional sports, e-sports) etc.

You dont watch/play dramas or horror movies/games cause they are "fun". Nor because they give you a nice fun pleasure (usually) but because they give you some kind of meaning, sense of fullfilment, a learning experience or a sense of being alive after all that tension and scares.

But honestly I dont think rage should be a feeling you should get from games or entertainment in general. In that I agree. But actually sometimes feeling hate or indignation/anger can make your "engine" move. I feel that those kind of feelings are a good fuel, they can become a creative/action force and the limit between those and rage is kind of blur. So I wouldnt criminalize it unless it affects other ppl in a harmful way.