How did this game get matched

i'm p1 with 53% winrate however in my ranked game my team was s4 (41% winrate) g1 (49% winrate) d5 (52% winrate) and d4 (52% winrate) the enemy team was no better match to my range g3 (54% winrate) g3 (50% winrate) p4 (58% winrate) p5(58% winrate) d3(53% winrate) the enemy people that were p4 and p5 had a chance to be in a game with me a p1 b/c of their winrates but how do golds and a silver with average winrates get matched in a game with low diamonds?