If I had to come up with a reason (with no industry knowledge), I'd posit the following: If MoviePass captures the ticket-buying market in a big way and become

If I had to come up with a reason (with no industry knowledge), I'd posit the following: If MoviePass captures the ticket-buying market in a big way and becomes the gatekeeper for consumer movie-going money, they could feasibly develop direct relationships with distribution companies in the film industry and drastically diminish whatever power theater operators currently have. As noted by others, there's a common belief theater profit comes largely from concessions. That defines their relationship with the consumer. MoviePass threatens their relationships on the other side, with the film industry, where we are the profitable product. That's my guess.