You are unable to understand what is being said clearly. Read what is stated. This game operates on a rank based system. It also has a downrank every season. These players "HAVE" been masters and pred, they are "ARE" prob gonna run over the whole lobby, but they "ARE" currently being matched in lobbies appropriate to their "CURRENT" rank.
Rookie aside. But if a former pred now plat player is whooping your * in plat lobbies, that is a problem with the "deranking" system that EA for some god awfull reason thinks is a good idea to have in the game still. Ergo they arent getting matched with players out of their rank, but they are gonna have to stomp worse players to get back to their original rank every season.