Now are they INTENTIONALLY feeding, or just getting dumpstered?
Are they deliberately trolling, or do you only feel trolled because matchmaking autofilled your mid laner against a 750K Mastery Point Yasuo OTP with a hard on and you cant do anything but see red from losing the coinflip?
There are a lot of factors that people throw out the window simply because they're getting pushed or knowing they're behind. Not everyone who feeds is inting - some are just getting ripped to shreds. Not everyone is trolling - some got trolled by matchmaking/autofill, and were never in the enemy's league to begin with. Me and my duo had an IRON 3 Kled in his SILVER 3->2 promos. We couldn't even be mad at the guy for losing (we were mad because he was first timing Kled jungle in ranked and even further dumpstered our odds of carrying him, but that's another story) because he was iron 3 against a M7 jungler who was GOLD FUCKING TWO last season...riot literally gave the enemy team the game, and rightfully, we were mad at the true cause of that loss - the complete offset of the spectrum was seen in that game.
Be mindful - the INTENT is bannable. The act of not having a 100%WR and getting chokeslammed by the enemy team is NOT bannable.