To be fair, I tried doing FC exp farming runs with Penguin some time ago and he kept running into spawns because the Despair Demons hurt his feelings or something. It can be incredibly frustrating when you're trying to milk the spawns and somebody messes it up. It's like back in mass effect when somebody would mess up a Glacier/Platinum speedrun by not blocking a spawn correctly.
It's the reason why the top players would rather solo or duo than let in a pug for those kinds of games.
And who cares? Its a casual game. So what if you miss out on some extra xp, stop being a baby and get over it. Isn't having fun the objective, or are you one of those people who play games for numbers, not enjoyment? I for one don't have fun being told how to play a game. I don't really give a sh*t if you get frustrated at losing a few xp points, don't tell people how to play a game that they 1) paid for and 2) chose to be in a lobby with you.