Most people don't consider the other side they're playing with. They think of it as a lifeless machine, in no way real or having any emotion or feelings. In conquest for trying to be the best, or win the game, they become so aggravated with players with lesser skill or different playing style that they simply won't tolerate it.
Know it or not, people are invested in the games they play. They believe that because of the time a person has put in they should be entitled to to an advantage. It's also the exact opposite where people have no time invested and seek to ruin the good time of other players. People generally feed off the misery of others. Why do you think theres so much trash TV, or celebrity gossip, or videos in which people get hurt or ridiculed go so high? It makes us feel better about ourselves. It makes us glad to not be that guy and happier with our own lives. Or its empowering to them to get attention or cause a reaction. Odds are they don't receive enough attention in their real lives and mill around the internet seeking for something or someone.
My advice: Fuck em. Find mature people to play with who are secure with themselves. Find people who don't need to win to feel satisfaction when the odds are against them. Find people that you can befriend and play with them. Its a process and its time consuming, but like most things in life good things usually are.