You know they did.
Dozens, possibly hundreds or even thousands of people spent several hours, every day, for months on end testing the hell out of that game, and for you to ask if QA even did their job is to be incredibly unappreciative of the work that goes into making a videogame.
Imagine you're a big AAA publisher and you've got a big new game coming out. You've got a 100-person team testing the game for 8 hours a day, 5 days a week, for 52 weeks of development.
That's 100×8×5×52 = 208,000 person-hours of testing.
Imagine your AAA game sells 1 million copies on your first day, and every player plays it for at least 1 hour. That's already 1,000,000 person-hours of playtime on the live game. That's 5 times longer than you tested it for, and this is only day one of the game's release. Imagine how many hours of gameplay will be racked up over the game's lifespan.
QA won't find everything. Maybe on a smaller title they'll come incredibly close, but on a big AAA project there's simply no chance that QA will find everything.
And even if they do, so what?
QA finding a bug means just that. They found a bug. That says nothing for the producer who'll have to determine its severity/urgency or the developer(s) who'll have to spend time isolating and fixing it.
Deadlines are pretty concrete things and publishers really aren't fond of moving release dates. If QA finds a bug, it'll be given a priority and the higher-priority bugs will have resources thrown at them sooner and the lower-priority bugs may miss the deadline entirely.
Please, have some respect for the poor QA testers who'll spend months of their life staring at the same levels over and over again. Have some respect for the developers who are trying to ship the best game they can within deadlines. Have some respect for the project managers who are having to make the tough choices about which bugs are absolutely critical to fix and which can be left to slide until a later patch.
Game developers are people too.