I think another key issue is that StarCraft is one of the more frustrating games to lose for some people. When I play a game of Ultimate and my team loses, I can usually understand what mistakes we made, what plays we let go that we should have stopped and where we were outplayed. It's still disappointing to lose, but it's readily understood when it happens.
SC2, in particular, has a lot of information asymmetry between the individual players, not just the spectators and players. When I lose a match in SC2 I feel dumb. I still know there's something I should have scouted, a change I should have made in my build order, somewhere I could have had some better micro, or even when I fell behind on my macro, etc, but I don't really know what, at the moment of my defeat, I should have done differently. So I go back, and I watch, and I see all my mistakes, and I see my opponent's mistakes, and I think, "Why didn't I push then? Why did I leave this point undefended for so long? Why did I make unit x instead of unit y?"
One figures out why one lost, but one has to go through the process of watching it all over again, and watching all one's chances to win just stroll on by.