Well did they have a bar? Or cooks that make you dinner? Or wait staff that bring you your food? These are things we traditionally have tipped for, they're just now in a movie theatre. Even if that wasn't the case every service industry business owner will try to claim that their staff gets tips so they can justify lowering their wage and pass on the responsibility of paying their workers fairly onto the customer.
That's why I don't order anything at the theater. Either I eat before I go, or have a meal afterwards at a different place. Sometimes I just bring a small snack in my pocket if I know I'll get hungry.
Some comments seem to miss the point of the article. Excessive hours, no breaks, long commutes, low pay (and low tips) are why some places are having trouble keeping staff. With profits soaring and exec pay ridiculously high, companies can certainly afford to pay better wages, hire more help, and offer benefits. But they don’t.
Also, don’t be an ass to the overworked, underpaid front line staff.