Ranked trolls

Why are there so many trolls in ranked? I feel lucky if I even get a single game without an afk, intentional feeder, or someone griefing because they didn't get what they wanted in champ select. The last game I played we had mid who threw a temper tantrum because someone banned Jhin and he wanted to play him mid. He proceeded to pick Singed and ran around the map all game, stopping only to try to throw Diana or Riven at our Mid or ADC-- all the while spamming "TROLOLOLOLOL!" in chat log, flaming the whole team with offensive language, and announcing how many blunts he had smoked and how high he was. My team almost won in spite of him but its frustrating when you actually get good teammates all except for one bad apple. It's really frustrating trying to grind out of bronze when this kind of stuff happens more often than not.

I don't mind losing but it is frustrating that my ability to escape bronze is solely dependent on getting enough games at the right time where I don't get afk's or deliberately toxic teammates. A team shouldn't lose LP if it is clearly evident that someone on the team deliberately sabotaged the game. Not that I expect anything to be done-- because it won't, but I just want to vent because it is hard to improve my play or enjoy the game when this kind of behavior is the norm and not the exception.