I think it comes down to communication from Universal to the park goers this morning. If the park employees were up front with everyone this morning and said "Hi all, there's technical issues right now and the ride won't start for a couple of hours after the park opens, and may go down throughout the day" then I put the onus on the guests to decide if they still want to queue up and take the risk they'll be waiting hours, and my not get to ride at all. They've been warned and decided to wait anyway.
If Universal said nothing and remained tight lipped about late start and potential down-time then I would say Universal is to blame for park goer misery.