We play LOL for fun

And it is not fun when someone rages on you for feeding. It happens to everyone, some more than others. But instead of complaining about the 0/10/0 or the 0/10/ . Instead help them. Tell the what they can do better. There is a difference in how you say this. If you say: STOP FEED, STUPID REPORT, it is not going to make him/her play better. Instead say this: Try to focus more on teamfights, or Buy a or a and try to play more defensive. This would help a lot of players. Just think that it wont do any good for your team if you rage.

P.S: I don't know if that is how you build but you get the idea.