Question About Ranked

I'm curious, I just played through my series, for some odd reason...I kept getting people who never played the champ or role they were in, are unranked, and clearly do not give a damn about anyone else. While the enemy team has people who know what they are doing. Like when I wasn't in my series I get the people that want to win. Why do I get people who are just....toxic....garbage....in my series? Is League designed to legitimately just go "Fuck you" on your series so you are forced to stay with people who just want to troll? I don't get it.