Hey everyone, our ______ has a score of x/y, and they're (insert insult here)
Honestly I see this in at least half of my games. I see it from people would consider friends. I don't understand what you possibly think you can get out of this. I'm pretty damned sure that the 0/3 riven top knows that 0/3 is a bad score, and is probably trying to get back into the game. But you complaining in all chat about how bad your teammate is playing is not going to help anything out at all. You telling your teammate how much they have(insert mental illness here) or how they need to(insert method of self harm here) isn't going to magically make your 1/6 lux mid suddenly have 2 more items and tear the enemy team apart. There honestly needs to be a report category specifically for this, as I see it so often from both my team and the enemy team.
Edit: The report shouldn't ban players, as this behavior is only worthy of a chat ban at most, but should definitely drop honor quickly.