You're arguing with someone about how they made the choice of purchasing a bad game.
"But it's fun!" they tell you. You ask them why? They can't tell you.
Fun is just a buzzword when you can't actually think of any real reasons as to why said game is good, and it's use should not be tolerated. It is used by people with buyer's remorse who can't recognize that the game they've bought is bad. If the game was genuinely good, you wouldn't have to defend it in the first place.
Being amused or entertained with something and being immersed are not the same thing. Some people can actually find themselves entertained with feces. They can be amused by it, but it won't change the fact that they're enjoying feces.
Us fellow Americans ask of you to ban the use of this word to justify opinions.