@Littumulkero There are a few reasons. First of all, the game uses a server authoritative model, which means that there's a different version of the game on the server calling all the shots. They probably don't want that version of the game to be accessible to everyone, hackers would surely take advantage of it and not just create more effective cheats, but also circumvent bans when boosting accounts, get access to other players account data or even to their devices.
Second, having private servers has the effect of fragmenting the playerbase, which means unbalanced lobbies and long waiting queues in areas with few players. Ultimately, this can lead to a premature death of the game.
Third, it's about stats. Players could farm for stats and badges easily in private matches, if they join in with a lot of friends. Sure this is possible even now, on normal servers, but EA and Respawn wouldn't be allowed to get tracked data / match logs from a private server and apply bans when it's the case.
