I like queuing up with other people I know not because of their skill, but their attitudes
Nothing tanks the games faster when everyone is bickering and focused on fighting each other instead of the enemy. Even if people have bad games, I rather have them because we have a chance of coming back when they are focusing on getting back on track rather than my teammates rqing or opening mid the second the team gold is 10 behind.
One of your teammates goes 0/10/2? I been there, seen that, and it sucks, but if no one rages at them, maybe they make some GREAT play in a critical moment and win the game for you, all it takes is people not harassing each other. Who knows, they might turn into 12/10/20 and it wont be bad.
When I make bad plays and mess up, I am already beating myself up, and when people spam mia pings and spit in my face to add salt to my wounds of making mistakes, I get upset and my motivation to play better becomes nonexistent. But if people just say nothing or just break the tension with a lol or neutral/encouragement, I try to do better next time.
I believe this game not only involves your skill and reflexes, but also the way you behave and how your other teammates behave, so I don't see what is the harm in having a more stable team by having people you know that don't rage on your team.