Feeding is the result of losing fights unless it's the result of intentional feeding, which is an entirely different monster.
Reducing deaths sometimes means giving up kills in exchange for surviving encounters, but while you miss out on the kill gold, so does your opponent. "Nothing ventured, nothing gained." That doesn't apply in League. Wasting your opponent's time is a great strategy. If they are on you and you deny them the kill, you deter them from using that time to get important objectives. There's this stupid popular idea that "Damage dealt to champions = best stat." Well, while that is important, looking at that stat after a loss is pretty pointless if you ask me. Champions are not objectives. Let me repeat that. CHAMPIONS ARE NOT OBJECTIVES. Stop chasing tanks, stop trying to duel fed champions because you're mad they won the last duel against you, stop trying to get "revenge kills." They don't carry games. They cause you to commit to kills and get tunnel vision away from objectives such as turrets, baron, dragon, and buffs. If even anyone reads this wall of text and applies it to a ranked game, you'll find it's true, and you won't stay one of these players the OP is referring to.
@OP: Screw you buddy. Players have bad games, and bad game streaks. Players like you with your stupid mouthing off keep them on tilt. Just stop typing and keep your advice to yourself.