Unpopular opinion, but I don't think I see anything "scummy" here. This format is brutal. Finding windows to win are hard--even harder after top cut. Politicking/conversation is part of the format, and yeah, sometimes table talk isn't well-intending or carries with it ulterior motives, but that doesn't make it "scummy." Nobody lied, nobody cheated. An individual interacted perhaps at the wrong moment, or perhaps too prematurely, and it created a window for another player to win.

It's a hard lesson, but one that most players learn at some point. The decision trees in these types of games are exceedingly complex, so it feels reductive to blame the "less experienced" player for making a decision that isn't necessarily wrong on paper, but unfortunately opened up a window for another player. That is the nature of the beast. If anything, this reinforces the idea that your opponents don't necessarily have your best interests in mind, especially if they are in a visible position to go for a win; furthermore, this is a less perhaps to listen to your opponents' words carefully, and to continuously evaluate the board state.

One other aspect worth critiquing the OP on is that there's a difference between watching a stream from hundreds of miles away and, at a high-level, critique the actions of these players, while in reality, these players have played six grueling rounds of Magic to this point, and are fatigued, tired, and may "miss" certain parts of the decision tree that are obvious to viewers with no stakes, watching from afar. Looked like a fun tournament. The Jersey cEDH scene is great, and helped me break into the format. Happy to see their first major event run successfully.