But it's not just a game; it is real life. In most stories like this, the game is literally the MC's job. It's their economic livelihood. Add in the betrayal of people the MC trusts, and the anger is completely understandable.
Saying they shouldn't get mad about it would be like saying someone shouldn't get mad that a colleague they trusted and were close to screwed them over, got them fired, and earned a major promotion as a result.
Because the game you were playing is just for fun while this kind of games are for making money online, not every game are for making friends and having fun
Your stand doesn't make sense because lots of people spend money on a game and devoted there lives on that singular game, so it's natural they would rage and feel annoyed that everything they build up is gone.
This is reality bro, what's make you think everyone can accept glitters and sunshine and just move on, you're clearly making a fool of yourself here. Betrayed, being used, being mocked what's make you think he will accept all that?
I dunno why but i find it so funny that in stories like this the mc always gets so mad and angry over a freaking game like if my friends kill me in game for a million id be like understandable have a nice day. Id just start over, like its just a game and thats money dude. It would be different if its real life but its literally just a game