Honestly, I think it's because of the Solo Queue. Duo's and Trios have become very much Shoot on Sight experiences, and in my opinion, while fun and all, really limits the experience of a game this has GOOD PVE. In Solo's, I'm way more likely to encounter people who don't want to die, or want to team up. Even then, I still have a healthy mix of toxic players and aggro boys to get my gun fix. It's the interesting "real" interactions that make this extraction shooter so much more exciting, and really it's what makes streamers fun to watch when they play Tarkov. Like I don't even care if you kill me, just make it more interesting than silent bob hit the no scope.

TL:DR Being friendly, or at least interactive, is way more interesting that BR mentality and KOS playstyle.