Complex sentence: Removing team-killers from a game, whether accidental or otherwise, is desirable to keep all players focused on the game, and avoid having a match thrown because of undue retaliations or a mismatch in skill.
Split into simpler sentences: Removing team-killers from a game, weather accidental or otherwise, is desirable, to keep all players focused on the game. And avoiding having a match thrown because of undew retaliations or a mismatch in skill.