Why Is It Acceptable For Players To Feed Every Single Game?

Note: This is not about behavior, but is about the logic and systems behind the game.

I've been losing quite a bit recently (on this account), despite having a lot of success on my other accounts. I keep seeing a revolving theme in almost every single loss -- there is always one player who feeds like there is no tomorrow. After checking several of them, it becomes apparent that this is not just an exception where they were having a bad game, or even a bad day for that matter. Some of these players feed horrendously literally every single match they participate in. One person I checked, averaged a little under 10 deaths a game (and this was including a couple remake games that only lasted 3 minutes).

I know it can't be a fun experience for these people, to be getting completely destroyed every single game.. Let alone for their teammates who have to play much better to make up for another player dragging them down. I understand that it's not against the rules to be bad, but wouldn't common sense dictate that there should be some level of bad where a line needs to be drawn (at least in ranked games)? What makes it acceptable for someone to continually be a burden to every team they join in a ranked match?

Would it not be better to have a maximum average death requirement, and for players who go over that, be required to play a certain amount of games in Normal matches before they can enter ranked again? Some games, you cannot help but die excessively. Perhaps the enemy team has someone snowballing out of control or maybe you're getting camped by the other team's Jungler... but to average something as ridiculous as 10 deaths a game is difficult for even the worst player.

Ultimately, definitely don't run into players like this every single game... so it's whatever. I really do believe that it might be better for everyone however if players who have major feeding problems like this weren't in ranked 24/7 however. Ranked isn't exactly somewhere people should be trying to practice or learn new things, and if someone is dying a TON every single game, more practice (not in ranked) would definitely be something they could use. Some type of system that corrals these players into that might be a lot more practical than to keep letting them run loose in ranked.

There could be some issues with the idea, but it sounds good in my head at least.