I have had quite a similar experience when I try to avoid flaming, so I've more or less resorted to muting most games.
However, when I don't mute people, I run into a certain problem that's probably due to my personality.
I generally see no reason to go after others as long as they aren't causing me and annoyance or anger. I don't attack teammates who are floundering if the seem intent on improving and contributing to the game.
However, when someone comes after me, I start having some troubles. One side of my family is the "sarcastic" side, who will tear you apart if you misspeak in the slightest manner. The other side of the family is the "robot" side, who don't understand non-fact based arguments and have a lesser regard for others' feelings. This makes for quite a bit of a personality for me. For this example, say I'm playing my main: jungle.
Here's a typical team conversation between that laner and me.
Laner:"WTF JUNGLE NO GANK ENEMY SEJ CAMP ME"
Me:"You were way too far overextended and she ganked you once. I'm not diving that full health enemy."
Laner:"lol stfu trash jungle come gank idiot"
Me: "You have died 4 times to the enemy laner BEFORE you got ganked. I'll gank another lane that WILL carry the game, thank you."
Laner: [All]: "LOL SEJ CAMP ME AND TRASH JUNGLER WON'T EVEN GIVE ME BLUE"
Enemy Team: [All]: "Stfu we don't care go cry to mommy"
Laner: "lol they're trash haha idiots"
Me: "You would die and lose blue. If they are trash, why haven't you won lane yet? If they're so trash, beat them 1v2 like Faker would."
Laner: "stfu kid i'm tired of your trash"
etc.