A help thread asking how to get back into PvE lobbies pulled 753 comments today. That isn't a help thread. That's a referendum, and the verdict is that nobody actually knows the rules of the system sorting them.
The top answer in u/Late_Championship_26's post is the line that did the damage. u/Happy_Rave laid it out: to stay in PvE lobbies you cannot shoot raiders at all. Shooting back counts. Defending yourself counts. The aggression score doesn't care who started it. u/Middle-earth_oetel, who flags himself as a PvP player, follows up by calling it a major design flaw, and the upvotes don't disagree.
This is the second day in a row the subreddit has circled the same hole in ABMM. Yesterday's version was about trial-lobby rats farming spawns. Today's is the inverse - the people who don't want to be there at all, asking why ARC Raiders keeps sending them back.
The counterargument exists and has been making itself heard. u/II-Jahr-II's mixed-lobbies-are-PEAK post cleared 800 with over 300 comments, and u/zx10racing's sharper version of the same take is sitting at a 0.68 ratio - meaning raiders are fighting it, not dismissing it. The shape of the argument is familiar. Mixed lobbies were the original promise. Behavior-based matchmaking siloed the player base into two flavors of predictable, and the middle - the part where you don't know what's coming - is what most of us showed up for. u/RossiferTaylor put it cleanly: the game was at its best when ABMM was an unknown and every interaction was a mystery.
Both sides are right, which is why the threads keep getting longer. The PvE crowd isn't asking for less risk. They're asking for the system to stop punishing them for refusing to roll over. The mixed-lobby crowd isn't asking for free PvP. They're asking for encounters where the other guy might be friendly to come back. Neither faction is being described by what ABMM is currently giving them.
The timing is part of the heat. We're on the eve of expedition departure - u/Happy_Rave flagged this in the same comment - and the population trends more aggressive in the last week of a cycle. The worst week to run a system that kicks self-defenders into sweat lobbies is the one we're in right now.
The lighter half of the day
Two threads kept the mood at 55 instead of lower. u/MattOverMind zoomed in on the Anvil's chamber and noticed the bullet has to curve out of the chamber to reach the barrel.

The top reply is a gif of something worse. Nobody is mad. Everyone wants to know which other guns are held together with duct tape.
u/Over_Translator9488 got himself locked in the Buried City metro after the train left, which is funnier the longer you look at the screenshot.

u/Gildian's reply - "you are now a zoo exhibit for the ARC" - did the work of forty patch-note paragraphs in nine words.
The thing that should worry Embark more than the matchmaking fight is u/eShivy's exploit clip, which u/Armroker confirmed in the replies is a known bug being triggered by third-party software. One line in that thread captures the pitch the room is at on cheaters: "I am praying this isn't a bug that can be consistently replicated." Two days after the fair-play statement.
Self-defense gets you punished. The exploit doesn't. That's the math going into the last week of the cycle.
"To get into PvE lobbies you not only need not to shoot first, you cannot shoot raiders at ALL. Shooting back will increase your aggressivity rating."
U/HAPPY_RAVE · ↑ 542 · R/ARCRAIDERS
"This game was at its best for me when ABMM was an unknown and every interaction was a mystery. Now there's very little middle ground."
U/ROSSIFERTAYLOR · ↑ 387 · R/ARCRAIDERS
"For the sake of both PVP and PVE players, I am praying this isn't a bug that can be consistently replicated."
U/FIRM_WORK_6807 · ↑ 434 · R/ARCRAIDERS
"You are now a zoo exhibit for the ARC."
U/GILDIAN · ↑ 218 · R/ARCRAIDERS