you might as just said, "hey you, 0/8/0 is a bad score!" You should listen to great players in sports (basketball, football whatever...) First words out of their mouth is never "boy you aren't making any baskets." They formulate things the teammate can try to do to turn the situation around. Then they give words of hope.
Really? Not only does your statement belittle the person you are speaking with, it is also inferring that your team has zero hope. Why don't you offer "hey guys, let's group top, and try to see if we can get a tower and couple kills?" Or, "hey, can we pressure mid and bot, and see if we can also secure the next dragon?".
I seriously do not understand why people feel the need to tell the person who just died 3 times in a row that he is dying too much. The kind of people that doesn't understand dying 3 times in a row is bad wouldn't play league at all.
I am sorry, I don't want this to come across as flaming you or anything, and no you can't get rid of negativity, but YOU SHOULD TRY.