I don't get pissed off AT a player because of fantasy. I admit I do get pissed off ABOUT a player.
I do know people who get pissed off AT players because of fantasy. Thankfully I don't have enough money vested to allow myself to get pissed off. I can understand those who "invest" significant amounts of money being not happy when a player underperforms. That's normal to me. "Pissed off" is extreme.
Forgetting fantasy, many people get pissed off at players, coaches, refs, during games. Myself included.
I went absolutely bat shit crazy towards Joe Maddon during game 7 of the 2016 World Series.
I'm a Cubs fan (fan - short for fanatic) who saw the most important sporting event (to me) of my lifetime take a terrible turn and I blamed him for it. In hindsight, I overreacted. At the time, it may have been one of the 5 most angry moments of my lifetime.