Reveal: ARC Raiders is indeed using player behavior as a hint for matchmaking. So passive/friendly players are more likely to play with other passive/friendly players, and shoot-on-sight players are going to drop into more-hostile lobbies, which is what players had been theorizing. I'm sure it also helps funnel cheaters away from regular players

https://www.eurogamer.net/arc-raiders-developer-confirms-player-behaviour-is-factor-in-matchmaking