I'm all for banning cheaters, but banning people because you are losing puts you on roughly the same level of maturity as griefers, and the squeaky little kids who swear a lot. You have to remember that the other people there are also playing to enjoy themselves, and part of the game entails winning or losing. Booting them because they win only serves to spoil their fun. There will always be people better than you at something, and you won't become any better by not playing them, so just learn to accept it as part of life, and part of the game.