why can two duos be on a team LOL

Legit just get two kids intentionally feeding while me and my buddy at least try to carry. Happened 2 out of 3 times we duoed we carried the one without the feeding duo since we didnt have one how convenient. this seasons actually fucking r%%%%%ed LOL. ofc these fuckers dont get banned either follows me around all game intentionally losing his duo a game spamming laugh. Cancer community and cancer matchmaking.