Why is autofill in Ranked?

First placement game, get autofilled support. Needless to say, we lost. Ranked is supposed to measure your ability, so why is it possible for you to get a position you have NO idea how to play, which btw just creates rage and toxicity and makes no sense. Personally, I think that keeping autofill as a feature of ranked is just going to lead to more bans and less enjoyable gameplay in the long run. Cheers!

Extra Edit: It happened again. 2nd match, but this time, flex. It's actually the most tilting thing on the planet. It's either dodge and get a loss or sit through 45 minutes for a slim chance to win when you're probably already going to lose anyway. It's just ridiculous. Edit: I have nothing against autofill in normals, where there is nothing on the line. Just with it in ranked.