Then what about the communication from the airline about blocked middle seats? I guess that was another lie? If United publicly announced that middle seats would be blocked, and people relied on that claim as part of their decision making to book a flight, and found the cabins are actually full, that is an unfair and deceptive trade practice and passengers have grounds to sue.

Either the seats are blocked or they are not - don't say they are and then run flights full, at best it's terrible optics at the wrong time, and it worst, it's outright fraud.