Phreak explains why unanimous surrender votes were removed in LoL Patch 13.7
Many League of Legends players have experienced a game where things are going wrong from the first minute. An early surrender vote will quickly follow for most of these games, but sometimes, one unfortunate player can hold the lobby hostage for longer by refusing to agree.
In Patch 13.7, however, the days of one person holding games hostage are finally coming to an end across all game modes from regular draft pick to ranked play. Developers have removed the requirement for a unanimous vote for early surrenders, giving teams a chance to leave matches that are destined for a Defeat screen.