why are new champs available in ranked first day?

This literally ruins the experience for players. for instance ive lost countless games today since the new champs were released today. and its not even that they are unwinnable its the fact people play first time new champ and ruin the gameplay for everyone. ive now had a rakkan mid and a xayah mid just to troll game and ruin it. i understand the fact that players should be able to play the new champs but not when they first come out in ranked. ive now lost 2 promos today from this alone from my team always picking the new champ.